Tachinid flies may resemble house flies at first glance, but they play a crucial role in the ecosystem. These flies come in various colors, sizes, and shapes, such as gray, black, or striped, and can be identified by their distinct abdominal bristles 1. As adults, they feed on liquids like nectar, as well as honeydew produced by aphids and scale insects [^2^].
These flies are particularly important for their parasitic behavior. Tachinid flies target the immature life stages of various insects, including beetles, butterflies, moths, earwigs, grasshoppers, sawflies, and true bugs [^3^]. By doing so, they help control the populations of these pests, making them a beneficial presence in gardens and agricultural fields.
As you learn more about the fascinating Tachinid fly, you’ll discover a diverse world of insects that contribute significantly to the natural balance within ecosystems. By understanding their life cycle, behavior, and impact on other insects, you can appreciate how these unassuming flies play a vital role in our environment.
Understanding Tachinid Flies
Tachinid flies belong to the family Tachinidae, which is part of the order Diptera. They are a diverse group, with over 1,300 species in North America alone. Some well-known genera in this family are Voria Ruralis and Lydella Thompsoni.
These flies are not the most striking insects, as they often resemble ordinary house flies. However, you can generally identify tachinid flies by their unique characteristics, such as:
- Stripes on their body
- Gray or black color
- Distinct abdominal bristles
Tachinid flies are essential for maintaining ecological balance. As parasitic insects, they mainly target immature life stages of various pests, such as beetles, butterflies, and moths. Helping to control these pest populations makes tachinid flies valuable allies for farmers and gardeners alike.
Adult tachinid flies have a rather simple diet, feeding on liquids like nectar and the honeydew produced by aphids and scale insects. This makes them beneficial pollinators, just like bees and butterflies.
When it comes to reproduction, tachinid flies have some interesting strategies. Females will either lay eggs directly on or inside the host’s body, or deposit them on the host’s food plant. This ensures that the larval tachinid flies have a ready supply of food once they hatch.
As you learn more about tachinid flies, you’ll appreciate how they play a vital role in their environments. From serving as biological control agents to pollinating plants, these small flies pack a big punch in natural ecosystems.
Life Cycle of Tachinid Flies
In the egg stage of the tachinid fly life cycle, adult flies lay their eggs on or near potential host insects. The selection of a host is crucial, as the developing parasitoid larvae depend on the host for nutrition and survival. Some tachinid flies are specific to certain types of insects, while others have a broader host range.
Once the eggs hatch, the larvae, or maggots, begin their parasitic relationship with the host insect. They penetrate the host’s body and start feeding on its internal tissues. The larval stage is the most destructive phase for the host insect, as the maggots eventually consume enough to kill it. The duration of this stage may vary depending on the tachinid fly species and their host.
After completing their development within the host insect, the tachinid fly larvae emerge and transition into the pupal stage. During this time, the pupae remain motionless and undergo metamorphosis. Pupation may occur inside the host’s remains or in the surrounding environment. This stage can last for several weeks, depending on the species and environmental conditions.
When the metamorphosis is complete, adult tachinid flies emerge from the pupae. These adults are responsible for continuing the life cycle by locating suitable hosts to lay their eggs on. The adults also contribute to pollination as they feed on nectar from flowers. The adult stage is relatively short, with some tachinid flies living only a few days, while others may live for several weeks.
The tachinid fly life cycle can vary greatly depending on the species. Some species complete only one generation per year, while others have multiple generations and finish their life cycle in 3-4 weeks 1. In any case, tachinid flies play a crucial role in biological control, acting as parasitoids to control populations of various insects.
Habitats of Tachinid Flies
Tachinid flies are beneficial insects that you can often find in various environments. They thrive particularly well in gardens, as there is an abundance of flowering plants and insect hosts for them to feed on. Some common habitats include:
Gardens: These flies are known to be helpful in controlling harmful pests. They can often be found around flowering plants and crops, assisting with pollination and pest control.
Soil: The larvae of tachinid flies develop inside their hosts, which usually inhabit the soil, such as beetle and moth larvae.
Tachinid flies are not picky when it comes to feeding, and you can observe them in action on different types of flowering plants. For example:
Asters: Tachinid flies can often be seen visiting asters, as they provide nectar for adult tachinid flies to feed on.
Crops: Since many crops attract potential host insects for tachinid flies, you might notice these helpful flies around your crop fields.
A good habitat for tachinid flies should include a variety of flowering plants that supply the necessary nectar for adult flies. This ensures a steady source of food, helping them survive, reproduce, and keep your garden or crops pest-free.
To attract tachinid flies to your garden, consider planting a diverse array of flowering plants. By doing so, you create a friendly environment for these helpful insects to keep your plants healthy and less susceptible to harmful insect infestations.
Role in the Ecosystem
Tachinid flies play a crucial role in maintaining the balance of ecosystems. They are known as beneficial insects, mainly due to their role as parasites and parasitoids of different insect pests.
Adult tachinid flies feed on insect honeydew and flower nectar, which provide them with energy for mating and searching for hosts. This process helps in pollination as they transfer pollen between flowers while feeding.
As biological control agents, the larvae of these flies parasitize various insect pests such as beetles, butterflies, moths, grasshoppers, sawflies, and true bugs. For example, the feather legged fly attacks stink bugs and leaf footed bugs, including squash bug and green stink bug.
In addition to reducing pest populations, tachinid flies also help increase the presence of other beneficial insects. Being natural enemies of pests, these flies indirectly aid in pest control and contribute to a balanced ecosystem.
Remember, tachinid flies play a critical role in supporting healthy ecosystems by acting as both pollinators and biological control agents. By reducing the population of harmful insects, tachinid flies maintain the delicate balance and promote the growth of beneficial insect populations.
Tachinid Flies as Garden Helpers
Tachinid flies can be a great help in maintaining the balance of your garden. They act as natural predators of many common garden pests, especially caterpillars. By doing so, they keep the populations of these pests under control, without the need for harsh chemicals.
These beneficial insects are parasitic, laying their eggs on the host insects, such as caterpillars and other pest insects. Once the eggs hatch, the larvae feed on their host, eventually killing them. This process is essential for maintaining the health of your garden vegetation.
As a gardener, you may find that using tachinid flies can be an eco-friendly way to protect your plants from various pests. They can be attracted to your garden through the use of plants with ample nectar, such as yarrow and cilantro, which serve as a food source for adult tachinid flies.
In conclusion, tachinid flies can play a crucial role in keeping your garden pest-free. By targeting some common garden pests, they allow your vegetation to thrive, while also reducing your reliance on chemical pesticides. So, next time you spot a tachinid fly in your garden, know that they’re quietly helping you maintain a healthy growing environment.
Key Preys of Tachinid Flies
Tachinid flies act as internal parasites, preying on various insects. One common group of prey they target is beetles. For example, they can be found attacking the larvae of the Colorado potato beetle and the Japanese beetle.
Concern for Butterflies
Sadly, butterflies and moths also fall victim to Tachinid flies. They can parasitize caterpillars of the Lepidoptera order, such as the cabbage looper, gypsy moth, and other moth species. The presence of Tachinid flies can pose a threat to butterfly populations.
Feasting on Bugs
Tachinid flies don’t discriminate when it comes to true bugs. They often target squash bugs, stink bugs, and similar insects. In one instance, feather-legged flies of the Tachinid family lay pale, oval eggs on the side of squash bugs.
Other Notable Preys
Other insects that serve as prey for Tachinid flies include:
- Grasshoppers: they can act as both hosts and prey for various species of Tachinid flies.
- Houseflies: some Tachinid flies resemble house flies, making them hard to distinguish.
- Armyworm: Tachinid flies can parasitize the larvae of armyworms, helping in controlling their population.
- Earwigs: specific Tachinid flies have been known to attack earwigs.
- Sawflies and sawfly larvae: they become hosts to Tachinid flies, eventually falling victim to the parasitic relationship.
- European corn borer: Myiopharus doryphorae, a specific Tachinid fly species, has been reported to parasitize this moth larva.
In summary, Tachinid flies have a wide range of prey, making them versatile internal parasites that can have both positive and negative impacts on ecosystems.
Management and Control
To manage and control tachinid flies, it’s essential to adopt an integrated approach. Since these flies are beneficial insects that control pests, you should focus on preserving their population to maintain a natural balance.
In your garden, avoid using broad-spectrum insecticides. These chemicals can harm tachinid flies and other beneficial insects. Instead, opt for targeted insecticides to control specific pest problems.
Here’s a comparison table of two management methods:
|Broad-spectrum Insecticides||Effective in controlling various pests||Harmful to beneficial insects, including tachinid flies|
|Targeted Insecticides||Minimally affects tachinid flies and other beneficial insects||May not cover all pest issues|
To promote tachinid fly populations, consider planting flowers they feed on. These insects prefer nectar-producing plants, such as Queen Anne’s lace and dill.
- Avoid broad-spectrum insecticides
- Use targeted insecticides for specific pest issues
- Plant nectar-producing flowers to support tachinid fly populations
By following these guidelines, you’ll be able to effectively manage and control pests while preserving the valuable natural enemy – the tachinid fly.
In this article, you’ve learned about the fascinating world of Tachinid flies. These unique insects serve an essential role in controlling pest populations, ultimately benefiting both farmers and gardeners.
Tachinid flies have evolved various methods of parasitism to successfully attack their hosts. This versatility allows them to target a wide range of insect pests. As a result, they are valuable for maintaining the balance within various ecosystems.
You can also benefit from these flies in your garden by fostering an environment that attracts them. By planting nectar-rich plants and providing shelter, you can ensure a thriving population of this helpful insect.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Tachinid Fly
Upstate New York
Location: New York
July 7, 2011 1:52 pm
I saw this bug in Upstate New York – I feel clueless as I bet it’s a very common insect I just don’t know.
Signature: Needing help from the Bugman
Dear Needing help …,
This is a Tachinid Fly, a member of the family Tachinidae. Tachinid Flies are parasites on other insects and they are considered highly beneficial. We believe with some certainty that your fly is Belvosia borealis which we identified on BugGuide, however, the most distinguishing feature, the yellow markings on the abdomen, are not visible in your photograph because of the angle of view.
Letter 2 – Tachinid Fly or Fungus Infection???
Fly with black and white abdomen…
December 23, 2009
I saw this Fly on the base of my porch light… most of the body of this fly is black or is of a dark color except the abdoman which has white stripes.
The temp. was around 25 degrees outside… the season is winter…
Though we cannot find a match on BugGuide, we believe this is some species of Tachinid Fly. Tachinid Flies parasitize other insects including caterpillars, and they are important biological controls for pest species.
Karl believes this is a Fungus Infection
I don’t know what kind of fly this is, is but think its flashy appearance could be due to a fungal infection, perhaps by Entomophthora muscae. There are numerous photos on the internet that look very similar to this this. The white banding occurs as the fungus bursts out between the abdominal segments (presumably just before the victim expires). For more information you could check out: http://www.hort.wisc.edu/mastergardener/features/insects/entomophthora/entomophora.htm or check out the photos at: http://magickcanoe.com/blog/2006/09/07/mystery-fly-and-crumby-internet-connections/
Letter 3 – Tachinid Fly from Australia
Subject: Colourful fly
Geographic location of the bug: Oak Beach qld
Time: 09:17 PM EDT
Your letter to the bugman: Spotted this beautiful fly. First time I have seen one like this. Just wondering what it is
How you want your letter signed: Rhonda
This is a parasitic Tachinid Fly, and according to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Some tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby.” Your individual resembles this colorful Tachinid Fly from New Guinea. The Museums Victoria Collection has a similar looking individual identified in the genus Rutilia. This Rutilia species on FlickR also looks similar, but not exactly correct. The Brisbane Insect site has images of several species in the genus Rutilia, and we believe the genus is correct, but we are not certain of the species. Tachinid Flies are called Bristle Flies in Australia.
Letter 4 – Bristle Fly from Australia
Please identify this fly
December 12, 2009
Hey bugman, whislt gardening I came across this fly, sitting in the sun, on a concrete pipe.
Its markings I have never seen before, and had to down tools and take a snapshot..its the only one I have as me getting close caused him/her to take off..can you help…and now I am on the hunt as I have never in my 40 odd years seen a fly like this..
Coningham, TAS, Australia 7054
We would not have expected such a distinctive looking fly to be so elusive to properly identify. We believe it is a Tachinid Fly, though we could not identify it on the Brisbane Insect Website, nor the Life Unseen website. There is a body of an Euamphibolia Fly on the Life Unseen website that looks quite close, but we could not locate another image to substantiate that. Perhaps one of our readers can assist with this identification. We also had a vague recollection of seeing a similar photo in the past, and sure enough, we found a still unidentified posting in our archive.
Eric Eaton Concurs
Yes, I do think the black and white fly is a tachinid, but have no idea how to explain it, or be able to be conclusive, either…..I’ll keep looking for an answer.
many thanks, I have sent the image off to the CSIRO head of entymology for id (if possible) it seems going from the other posting earlier that it is in the same area Cygnet is approx 15 mile from my area.
just in time for christmas, if i receive a response from CSIRO i will let you know, thanks again for responding so quickly..
December 16, 2009
I have a name !
response from CSIRO
This is a bristle fly, Amphibolia vidua (Tachinidae), one of perhaps 3-4,000 species of this family occurring in Australia. Its larvae feed as a parasite internally on other insects. On sunny days in summer the adults often rest on smooth eucalypt tree trunks, and similar structures such as poles and pipes.
Thanks again Daniel.
Letter 5 – Tachinid Fly: Microtropesa sinuata
Subject: A fly?
Location: Coimadai, 50km north of Melbourne Australia
January 26, 2014 11:28 pm
Hi I found this fly attached to my pants while visiting the Merrimu Resevoir near Coimadai, about 50km north of Melbourne, Australia. It was approx 1.5cm in length and caught my eye due to its bright colours. Thought I’d share as it’s quite fascinating. Is anyone able to tell me what it is?
We suspected that this is a species of Tachinid Fly, a large and diverse family whose members parasitize other insects and arthropods, and many species are considered important biological control agents. We searched the Brisbane Insect website, and found a striking similarity between your specimen and two examples of Tachinid Flies in the genus Microtropesa, which are known as Golden Tachinid Flies. We searched for additional examples of that genus and we found another example that looks exactly like your individual on the Diptera Info website, but it is not identified to the species level.
Update: Microtropesa sinuata
We received two comments with links to Life Unseen and the identification of this Tachinid Fly as Microtropesa sinuata.
Letter 6 – Tachinid Fly
Subject: help me identify this fly
September 10, 2012 2:48 pm
I found this fly in front of my house.I live in Quebec,Canada.In a small town called Baie-Comeau.I’ve never seen such fly arround here and no one I know either…It was half inches long and about same wide with the wings.
wSignature: Pierre Murray
This distinctive fly is a Tachinid Fly, and we believe the species is Hystricia abrupta based on images posted to BugGuide. The range is also consistent with your sighting. Tachinid Flies are important parasites that prey upon a variety of insects and arthropods. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 7 – Tachinid Fly on Catalina Island
Subject: What is the name of this fly?
Location: Catalina Island
August 4, 2012 2:08 am
I saw this interesting fly on a plant on the Wrigley Botanical Garden and could not find it listed in any Catalina Island guidebook. I believe the order is Diptera. Can you identify the family, genus and species, please?
This is one of the Tachinid Flies in the family Tachinidae. Tachinid Flies are a diverse family, and according to Charles Hogue in Insects of the Los Angeles Basin: “Most species of this group resemble overgrown House Flies but are covered with extra-heavy stiff bristles. The thorax is usually a solid color and is not banded lengthwise as it is in other domestic flies. Tachinid Flies are often seen flying closely over or crawling through low vegetation in search of insect larvae (cutworms and the like) upon which to lay their eggs. The larvae are parasitoids that feed internally on the host; as the hosts are caterpillars, including cutworms and loopers, Tachinid Flies are considered beneficial to the gardener and farmer.” We believe this is the Spiny Tachina Fly, Paradejeania rutilioides, based on images posted to BugGuide and the range which is the southwest portion of North America. Often island populations evolve into distinct subspecies and we are not certain if this is the case with the Santa Catalina Island population. BugGuide lists the host as the larvae of Edwards’ Glassy-Wing, a species of Tiger Moth that feeds on oak in its larval stage.
Letter 8 – Australian Tachinid Fly appears to be Formosia speciosa
What is it?
Found by a friend in her garden in cygnet, AR Australia
We are relatively certain this is some species of Tachinid Fly, but sadly, we cannot find a species match on the awesome Geocities Tachinid Page. All Tachinid Flies have larvae that are internal parasites on insects, especially caterpillars, beetles, true bugs, grasshoppers and stick insects.
Update: November 29, 2010
A new set of images of this lovely Tachinid or Bristle Fly has allowed us to clean up this previous unidentified posting.
Update: January 25, 2014
Some recent comments on this posting by John Morgan have caused us to question the possibility that this might NOT be Amphibolia vidua. The black markings on the white abdominal area on this fly appear to be different than the 2009 Bristle Fly posting we created and the 2010 Bristle Fly posting we created that we have identified as Amphibolia vidua. Does this represent individual variation, a different subspecies, a different species or a completely different genus? We cannot say for certain. Perhaps an expert in Tachinid Flies will be able to sort this out. We are still awaiting John Morgan’s photograph for comparison.
Update: December 15, 2014
After an extensive exchange with Marlies, we are now relatively confident that this Tachinid is Formosia speciosa.
Letter 9 – Tachinid Fly: Belvosia borealis
Subject: What species of fly is this?
Location: Clinton, Maine
August 18, 2017 1:48 pm
This is a fly my son found in our flower garden. It is summertime here in Maine and I don’t recall ever seeing this fly! We have many living next to a farm, but this little guy is quite exquisite! Can you tell me what he is please?
Signature: Kristy Richard
This is a parasitoid Tachinid Fly, and we are quite confident it is Belvosia borealis because of its similarity to this BugGuide posting, also from Maine. According to BugGuide, the larvae feed “on Ceratomia spp. (Sphingidae).”
Letter 10 – Cricket with Parasite
What is this parasite on the cricket?
September 1, 2009
We found a wild cricket with the lump on its side. We were not sure if it was a growth or a parasite. Later I found another one and removed the lump. It appears to have legs and was attatched at only one point. The pictures show one with the parasite attatched. The other shows the underside of the parasite.
David and Deanna Brown
Clark County Indiana, in a garden.
Hi David and Deanna,
About a year ago, we posted a similar image and surmised that it might be a Tachinid Fly that had parasitized the cricket in question and linked to an online article on Tachinids parasitizing Crickets. Eric Eaton then provided us with this information: “Hi, Daniel: The object protruding from the deceased cricket is indeed a fly puparium (the rigid last larval ’skin’ enclosing a fly pupa). It could certainly be a tachinid fly, but there are also other flies that are parasitic on crickets, especially some members of the flesh fly family (Sarcophagidae). I’d personally be hard-pressed to identify even the adult fly once it emerges, though a dipterist (fly expert) could. Eric” We will contact Eric Eaton to see if he agrees. The most common cricket parasite written about online is a Horsehair Worm.
Eric Eaton offers a suggestion: Rhopalosomatid Wasps
The cricket parasite is probably not a tachinid. See this:
Wish I had more time to expand on this, but I don’t at the moment.
Letter 11 – Tachinid Fly Pupae and Adults
Hello again, Daniel.
Apologies for two messages in one day, but our earlier correspondence reminded me of something. Back on June 25th I sent you a couple of photos of a questionmark caterpillar that I’d mentioned had later been parasitized by a tachinid fly, which was also raising havoc with my monarch caterpillars. In answer to your request, I had to say I hadn’t photographed the fly.
Anyway, since then, I’ve kept several of the little maggoty buggers in a medicine bottle, allowed a few to emerge, and then put them in the freezer. I remembered today, after another monarch was killed. Here’s a mug shot. The “pills” are their pupal cases. I don’t know the species, and I don’t care!
Like so many of these flies, they emerge when the caterpillar is in the process of going into it’s pupal stage, or sometimes even after the chysalis is formed. Then the maggot comes out, and rappels to the ground on a long filament, and upon finding a spot to it’s liking, becomes a pupa itself.
I understand these amazing creatures role in the natural world. I’ve read alot about their incredible lifecycle. But I love moths and butterflies more, and these little monsters seem to take perverse pleasure in killing my favorites right at their peak, after they’ve gone through their entire laval stage. I hate them!
Anyway . . .
Cheers, and thanks very much for all you do.
Don J. Dinndorf
St. Augusta (central), Minnesota
Thank you for providing such an educational posting on the life cycle of Tachinid Flies for our readership.
Letter 12 – Tachinid Fly
Subject: Fly, Hoverfly, or what?
Location: Columbus Ohio
July 6, 2012 3:29 pm
Saw this largish fly type insect on my roses, and wondered what it was. You’ll see it’s on a standard rose leaf, so you can see the size fairly well.
Though we never know the species without looking it up, we can at least identify many Tachinid Flies to the family level. Tachinid Flies are a large family and they often have bristly bodies. They are parasites that prey on a large variety of arthropods. BugGuide states: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.” Unless this combination of markings is more common than we suppose, we believe we have correctly identified this Tachinid Fly as Archytas apicifer thanks to BugGuide.
Letter 13 – Another Tachinid Fly: Belvosia borealis
Tachinid Fly: Belvosia Borealis
June 3, 2010
This fellow landed in a Chestnut tree today long enough for a few shots. I easily indentified it from a photo posted on your website. If I ever ran across one of these before I don’t remember it. (Probably just never noticed it) I do think I would have remembered the bumblebee colored butt though. Thanks for all you do and have a wonderful day.
North Middle Tennessee
Thanks for sending us your excellent images of Belvosia borealis, a Tachinid Fly. While the larvae are parasitoids, the adults feed on nectar and pollen as evidenced in your photographs.
As a point of clarification, with the scientific binomial system of naming living things, the first word represents the genus name, and it is capitalized. The genus is a grouping of closely related species. The second word is the species name and it is written in lower case.
Letter 14 – Argentine Tachinid Fly introduced to Australia as biological control agent
Location: Queensland, Australia
September 30, 2011 11:23 pm
Thought you might like these shots of Trichopoda giacomellii, introduced into Australia from South Africa as a biological control agent for Green Stink (Potato) Bugs. Sure are pretty for assassins.
Thanks so much for thinking of us when you have another gorgeous image of some Australian bug that is underrepresented on our site. Armed with the information you provided, we tried to find additional information on this Tachinid Fly, and we learned that it is originally from Argentina, not South Africa. You can verify that both on this PDF courtesy of the CSIRO Division of Entomology and the CSIRO website. According to the Queensland Government Primary Industries and Fisherieswebsite, this Tachinid is commonly called the Green Vegetable Bug Parasitic Fly.
Letter 15 – Beelike Tachinid Fly
One ugly fly
I looked through your site but did not find this fly anywhere. What is it? It was found buzzing around in Point Lobos State Park, near Carmel, CA.
This is a new species for our site. It is a Beelike Tachinid Fly, Bombyliopsis abrupta. The adults drink nectar, and the larvae are internal parasites on caterpillars.
Letter 16 – Beelike Tachinid Fly
Red, spiky fly?
This guy flew into a leaf and fell in front of me last week when I was in upstate New York…I’ve never in my life seen a bug like this. He must be some variety of fly, could you please tell me what he is, exactly? I don’t mind how long you take to answer, even if it’s like, 2 months. I understand you’re busy, so if nothing else, at least I can give you a cool photo of a weird bug! Thank you very much!
The Beelike Tachinid Fly, Bombyliopsis abrupta, is an important biological control agent. They parasitize caterpillars.
Letter 17 – Black Tachinid Flies on Goldenrod
Subject: fly wings be body
Geographic location of the bug: Shade Gap, Pa
Time: 04:53 PM EDT
Your letter to the bugman: Hello,
I always pay attention to the insect world and the pictures I have I will send to you hoping you know. I have lived in the mountains for a long time and the bug I am seeing on flowers has fly wings but a bee body. This is the first year I am seeing these
How you want your letter signed: Eric J Mazzi
This turned out to be a very easy identification for us. We had a general ID upon looking at your image of parasitoid Tachinid Flies, a group of insects that are important pollinators as adults, and with larvae that parasitize various groups of insects and arthropods. Tachinid Flies are very host specific. Some species will only prey upon caterpillars from a single family, genus or even species, while others are just as picky about preying upon Spiders. We quickly identified your Black Tachinid Flies as members of the genus Leschenaultia thanks to this BugGuide image, and according to BugGuide: “recorded hosts include various Arctiidae, Malacosoma (Lasiocampidae), Hemileuca (Saturniidae), and some other moths.” Your image is also the first we have posted this year of goldenrod, so we are tagging it as a Goldenrod Meadow posting.
Letter 18 – Bug of the Month June 2011: Tachinid Fly
May 29, 2011
Though this letter was submitted nearly a year ago, we discussed with Frederique Lavoipierre the possibility of making the Tachinid Fly the featured Bug of the Month for June 2011.
What is this bug?
Location: Cloudcroft Observatory, New Mexico.
September 10, 2010 4:11 pm
Hello. I was curious about a bug I saw in the mountains at Cloudcroft, New Mexico. This bug was found at the Cloudcroft Observatory. It seemed a lot like a bee because it buzzed, but it looked totally different than one.
This bug was seen in August, 2010.
The color palette of your photograph is so beautiful. This is a Tachinid Fly, probably Adejeania vexatrix based on images posted to BugGuide. Adult Tachinid Flies take nectar from flowers, but immature larvae are endoparasites on a variety of insects and arthropods, often limiting themselves to a single species.
Bug of the Month
May 29, 2011
We are taking this opportunity to make our readership aware of the beneficial flies in the family Tachinidae by linking to the BugGuide information page on the family. We are also providing a link to the Pacific Horticulture website and the online article on Tachinid Flies submitted by Frédérique Lavoipierre, Garden Ecologist. Here is an excerpt from that article: “Tachinids are the most diverse family of Diptera (true flies), and help control many pests; of the parasitic insects, only parasitoid wasps are of greater importance. All of the known species of tachinids are parasitoids: they deposit their eggs on or near host arthropods, and the larvae parasitize the host, in most cases resulting in the victim’s death. Parasitoids (as opposed to parasites) are free-living as adults; many of the common garden tachinids are flower visitors, feeding on nectar and pollen as adults. Tachinids parasitize a broad range of hosts from several orders of insects, among them Lepidoptera (butterflies and moths), Coleoptera (beetles, especially scarabs and leaf beetles), and Orthoptera (grasshoppers and crickets). In the Hymenoptera (wasps, bees, and ants), they specialize on sawflies, a common herbivorous pest. They are also known to attack a few other arthropods besides insects, particularly centipedes.”
Update: June 29, 2011
Took me a bit longer than I thought to wrap up my thesis, and someone in the department just pointed out the tachinid ‘bug of the month’ to me yesterday. At any rate, it was very cool to see tachinids in a starring role!
Letter 19 – Caterpillar and Parasitoid
Subject: Mother & babies or mass parasitism?
Location: Altadena CA foothills (chaparral)
June 18, 2017 7:08 pm
We have no idea what’s happening here… I strongly suspect parasitism?? Forwarding the photo to What’s That Bug for consultation!
Signature: Lori & Neighbors in Altadena
Dear Lori and Neighbors in Altadena,
This Caterpillar is definitely the victim of a Parasitoid. Alas, we don’t think we will be able to accurately identify either species. The Caterpillar appears to be an Inchworm in the family Geometridae, but we would need to see the prolegs to know for certain. We suspect the parasitoid may be a species of Tachinid Fly.
Letter 20 – Featherlegged Tachinid Fly
flies or bees?
flies or bees? i’m guessing flies by the eyes. are they similar because they hold their wings out straight? both about 1/2 inch long.
We wrote to Eric Eaton to try to get a species name for your fascinating fly. Here is his response: ” Yes, that is a featherlegged tachinid fly in the genus Trichopoda. They are parasites of leaf-footed bugs and squash bugs, rarely stink bugs. Those raised white spots on the head or thorax of a leaf-footed bug are the eggs of this and related species in the genus. Eric”
Letter 21 – Large Spotted Acrea Caterpillars bothered by Tachinid Fly
Location: Kinshasa, Congo
January 2, 2012
Thanks for the additional information on the caterpillars. We went back yesterday to the same location where we found the Acraea zetes menippe and saw a whole lot more caterpillars. There were quite a few climbing up a certain plant and regrouping in clumps of 5-10 individuals. We photographed a group on one of the leaves they were eating and filmed some interesting behavior. Where the caterpillars were in a group, they seemed to react to flies. As flies approached, they all started flailing their heads in the air. We tried to reproduce the behavior by tapping on the leaf and blowing on the caterpillars but they only seemed to have that reaction to approaching flies. The video can be viewed here:
A few pictures of the group on the leaf they were feeding on and one of a solitary caterpillar found nearby also attached.
Katy and her Dad
January 4, 2012
Keith and Daniel,
We hope you had a great New Year celebration. We are intrigued to get your opinion on the behavior witnessed by a group of Acraea zetes caterpillars that we saw a few days ago. We sent an email will additional photos of the caterpillars on one of their food source leaves but the internet connection has been very problematic. Please confirm receipt or we can send again, one image at a time. The video can be viewed here:
Katy and Nick
Keith Wolfe responds
Katy, Dad, and Daniel,
Let’s pretend for a minute that these seven caterpillars are the five of us (mustn’t forget Mom) and two friends having a picnic, when suddenly a never-before-seen ginormous (relative to our size) fly starts buzzing around. Bugman and I would probably be snapping photos and otherwise documenting the encounter for a scientific paper, but fast forward 1000 generations, when by now natural selection has honed our behavior to instinctively recognize these tachinid flies (http://en.wikipedia.org/wiki/Tachinidae) as mortal enemies — parasitoids whose reproductive strategy is to lay eggs inside our soft, slow-moving bodies so that their ravenous offspring will survive at our expense. With that in mind, we too would be wildly flailing our heads, arms, and bodies, along with regurgitating bitter intestinal juices as an added deterrent.
That is great information and it explains why the caterpillars were not phased by tapping on the leaf or blowing on them but when they heard the flies nearby, they went into hyperdrive with the flailing.
January 12, 2012
Dear Katy, her Dad and Keith,
Thanks so much for supplying additional photographs and a wonderful explanation of the parasitic habits of the Tachinid Flies with regards to Caterpillars. We have been on holiday for the past week and just returned, which we hope explains our lack of input in this posting.
Letter 22 – Mating Tachinid Flies
More bug love
Attached are a few images of a mating pair of some wonderfully colored flies. I love the furry collar around their necks, not to mention the huge red eyes. The images of the lone fly are of, I assume, the female after the male has flown off. They were very kind to stay still while I got in close to take their picture. I would say they are no larger than a 1/4 inch long. Any idea what they may be? The images were taken April 18, 2008 in a small field of mallow and grass in Mountain View, CA. This was probably the first week of the year temperatures reached over 80 degrees. All the bugs are finally coming out of the wood work. Thanks in advance,
What a marvelous image of mating Tachinid Flies in the genus Gymnosoma. According to BugGuide, adults feed on nectar and the larvae are parasitic on Stink Bugs in the family Pentatomidae.
Letter 23 – Mating Tachinid Flies from Italy
Subject: Bug Love – Flies from Italy
Location: Italy (Lazio)
October 6, 2014 3:59 am
These two flies were flying around one on top of the other, and they eventually landed on a plant.
I am not particularly curious of the species. I just wanted to send you this for the Bug Love section.
Our hunch was that these were mating Tachinid Flies, and upon doing some research, we found we are correct. We initially identified them as Ectophasia crassipennis on the Insects of France website where we learned: “This fly lives in southern Europe and in the warm parts of Central Europe. Not in the Netherlands like some other members of the subfamily. … Males and females are different. The brownish yellow abdomen of the male has a wide black stripe. The female lays the eggs directly into the host the shield bug (Pentatomidae) Length 5 – 9 mm. May – September.” We verified the identification on another French site.
Letter 24 – Parasitic Tachinid Fly
Subject: Maybe a tiger bee fly?
Geographic location of the bug: Louisville, KY 40299
Time: 11:00 AM EDT
Your letter to the bugman : Good day sir, this (not so little) guy was hanging out on my front porch and wasn’t too disturbed by me getting my phone very close for these striking images. I placed a penny near it in a couple of photos so you could have a sense of scale. Wondered what exactly it is and if it is dangerous in any way. Thanks kindly!
How you want your letter signed: Wayne H
Daniel just published an identification request for a Tiger Bee Fly, which is definitely not your fly. This is actually a Parasitic Tachinid Fly in the family Tachinidae, a group with many individuals that are covered with course hairs, so they are sometimes called Bristle Flies. Your individual appears to be a member of the genus Leschenaultia which is pictured on BugGuide where the host prey is identified as members of several moth families. Insects that are parasitoids, meaning the eggs are laid on the bodies of host insects which are eaten alive, are often very specific about the host prey which is sometimes limited to a single species. This fly poses no threat to humans.
Thank you so much for the information!
Letter 25 – Tachinid Fly
Subject: tiny and pretty fly
Location: Wildwood picnic area, Angeles National Forest
August 25, 2016 10:37 pm
This cute little thing I found in Angeles Forest today. I am stumped as to what it is. It was very small. Is it a Pokemon?
Signature: Jessica Chortkoff
We believe this is a parasitoid Tachinid Fly, but we cannot find any matching images on BugGuide, though we have to admit, we just browsed. We will try to get a second opinion.
Eric Eaton writes back.
I did find it on Bugguide using the advanced search for Tachinidae in California….
Letter 26 – Possibly Tachinid Fly from New Zealand
Subject: Bristle fly
Location: Mokotua, near Invercargill, NZ
April 23, 2013 1:35 am
Hi there. This photo was taken in the autumn here, late in the day. The fly is on a Juncus rush, near a wetland area, with lots of native vegetation dominated by manuka. Hope the photo is clear enough.
We believe this is a Tachinid Fly in the family Tachinidae. See BugGuide for additional information. The larvae of Tachinid Flies are internal parasites that kill their insect and arachnid hosts. Generally each species of Tachinid Fly is very host specific, so they are important biological control agents.
Thanks very much for that information. Confirms what our local bugman suggested, but interesting to hear that these flies are host specific and potentially a part of controlling pest species. Your time on this one is much appreciated. That’s an excellent website and resource you have there.
Letter 27 – Presumably a Tachinid Fly from the Canary Islands
Location: Tenerife, Costa Adeje
November 26, 2011 11:52 am
Photographed this fly earlier this year but cant identify it at all.
Shot taken in San Eugenio Alto close to a Banana Plantation.
Signature: Dave Wilson
We needed to do a web search to determine that your location is in the Canary Islands off the west coast of Africa. We are relatively certain your fly is a Tachinid Fly, a member of a large family with members that parasitize insects and other arthropods. Different species of Tachinid Flies are often very host specific, concentrating on a single species or genus as their host. The female Tachinid Fly lays eggs on or inside the host and the larval flies develop as internal parasites, eventually killing the host. Tachinid Flies are important biological control agents.
Letter 28 – Probably Tachinid Fly from New Guinea
Subject: tropical fly
Location: Highlands, Papua New Guinea
January 31, 2015 12:16 am
Found this in our village where we work as missionaries. Never seen anything like it and am wondering what kind it is. (See attached pic)
Signature: David Ogg
This is a beautiful and colorful Fly, and we are relatively certain it is a Tachinid Fly in the family Tachinidae. Tachinid Flies are parasitoids. The female lays an egg on a very host specific prey, and the larval Tachinid Fly feeds on the internal organs eventually killing the host, at which time it will form a puparium and eventually emerge as an adult Tachinid Fly. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.” We are attempting to provide you with a species identification for this distinctive, probable Tachinid Fly. The Tachinid Collection pictured on Tachinidae Resources includes Rutilia (Donovanius) regalis, which looks similar to your individual, but we are not even certain of that species’ range.
Letter 29 – Spiny Tachinid Fly
October 9, 2011
in paso robles yesterday, this very bristly, large beastie flew away from its mates on the coyote bush into the house. he was fearsome-looking, but didn’t mind being caught in a jar and released 🙂
this guy had definite orange spots. i looked him up in the book i have in paso robles, but forget its name – the fly and the book…
Ed. Note: This came to Daniel’s personal email address from a close friend. Here is some of the email chatter.
Julian Donahue provides some input
Tachinid, all right. Perhaps one of the ones that parasitizes the wild silk moths, like Hyalophora euryalus (that’s the name of the moth, not the fly). There are also some big ones that parasitize earthworms.
he looked big enough to parasitise anything his little heart desires!
i have only ever seen them in the fall… could that be?
ooh – yes, that’s him (her?).
Tachinid Fly – Paradejeania rutilioides
they were all over the baccharis.
it’s a lovely camera. but, the beast was inside the house and i was outside the window shooting thru not exactly recently-cleaned glass. further, the beast was high on the rolled up blind – and i was on my tiptoes – wobbling
BugGuide reports them in California from August through December. BugGuide also notes: “Adults take nectar, especially from late blooming Asteraceae. Larval host: the arctiid moth Hemihyalea edwardsii, at least in part of its range (Hsu & Powell 1992).” Surprised Julian didn’t know that Arctiid host tidbit.
Letter 30 – Tachinid Fly
Just curious as to what kind of fly this is. I took this picture in the springtime in southern New Jersey. The fly was probably a half inch long and sitting on some small flowers. I included the flowers when I cropped the picture in case it helps with the identification. Thanks!
This looks like a Tachinid Fly to us, probably in the genus Archytas according to images on BugGuide. Immature flies, the maggots, are intermal parasites on a variety of insects.
Letter 31 – Tachinid Fly
I am from Zanesville, Ohio (Southeastern Ohio) and we were enjoying a hot summer day around the pool. I found this guy flying around the house and tracked him down thinking it was just a horsefly that had gotten indoors, when I swatted him, I noticed that he was completely different. The creature has fly-like wings and head, but the rearend of a bee. It has two large thick yellow stripes with spikey black rings separating them. It was truly one of the weirdest insects I have ever seen. Do you have any idea what this is? I have looked online through the Ohio insects and have not seen ANYTHING close to this type of a fly, or bee for that matter. Can you help? Thanks so much.
This is a Tachinid Fly, and the genus is Belvosia. Sorry, but BugGuide does not divide the genus into different species and there is no common name. Tachinid Flies in the family Tachinidae are important biological contols of many plant eating species because the larvae are parasitic on a variety of insects and arthropods, with caterpillars being most common. The female fly lays her eggs inside the host and the larvae devour the caterpillar from within, pupating inside the host, and emerging as adult flies.
Letter 32 – Tachinid Fly
Please tell us what kind of bee this is….
We live in the Rocky Mtns just west of Denver. Elevation about 9000. Thanks,
Are you sure? The tachinid on the site looks yellow where this one is so orange and this one hangs on the flowers like a bee…..
Ed. Note: On occasion, in an effort to respond to as many readers as possible, we reply with a general identification. We have also misidentified more specimens than we care to admit. This is a Tachinid Fly in the family Tachinidae. According to BugGuide, this is the: “second-largest family in the order Diptera (behind Tipulidae) 1,345 species in 303 genera in North America listed at Tachinidae of America North of Mexico by O’Hara and Wood.” We do not have every single scientific name committed to memory, and it takes time to looks them up, so we gave a general answer as to the family. Since many Tachinid Flies do not resemble the one in the photo, our reader was confused. Upon being questioned, we decided to give a more specific answer. The fly in the photo is in the subfamily Tachinae. It may be Adejeania vexatrix, but we are leaning towards Paradejeania rutilioides, the Spiny Tachinid Fly. We fear that exact species identification is beyond our means as this generally requires a specialist, known as a Dipterist, and a physical specimen to examine. We are artists, not dipterists.
Letter 33 – Tachinid Fly
I was wondering if you could tell me what this insect is? I saw it while hiking at Golden Gate State Park in Colorado. Thanks!
What a beautiful action photo of a Tachinid Fly. We are currently experiencing some technical difficulty, and we can post letters, but new photos are not appearing on the web. We have contacted our web host to see if he can correct the problem. We believe your Tachinid Fly is Adejeania vexatrix based on BugGuide. BugGuide also states that this Subfamily of Tachinids, Tachininae, parasitizes caterpillars.
Letter 34 – Tachinid Fly
Yellow fly with a big red bottom
Sun, Feb 8, 2009 at 12:12 AM
This fly I found going between dandelions in Colorado Springs. It has big red eyes and a big red bottom with black hairs, and a more yellowish head. What is it?
This is a Tachinid Fly, probably in the genus Adejeania which can be substantiated on BugGuide. One on the submissions to BugGuide mentions the huge palps of the genus as being distinguishing features, and your photo illustrates this nicely. Tachinid Flies often visit flowers as adults, and the larvae are parasitic, often on caterpillars. Here is what BugGuide has to say about the parasitism of Tachinid Flies: “Larval stages are parasitoids of other insects. Almost every order of insects is attacked by tachinids, including a few types of non-insect arthropods. Some tachinids are very specific and others can parasitize a wide variety of hosts. The most common hosts are caterpillars.
Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 35 – Tachinid Fly
What is this fly?
Wed, Jun 3, 2009 at 8:59 PM
I took this photograph at 4:27 pm June 03, 2009 in the Central Okanagan region of British Columbia. The area it was specifically taken in is characterized by grasses and sagebrush. The temperature was about 30 C and sunny. The fly appeared to be feeding on the flower it is currently sitting on (a popular choice as several other bugs were photographed on the same type of flower).
Westbank, British Columbia, Canada
This is a Tachinid Fly in the genus Cylindromyia, according to images posted to BugGuide, which indicates they are a “common flower visitor in open weedy areas. ” Of Tachinid Flies in general, BugGuide indicates: “Larval stages are parasitoids of other insects. Almost every order of insects is attacked by tachinids, including a few types of non-insect arthropods. Some tachinids are very specific and others can parasitize a wide variety of hosts. The most common hosts are caterpillars” and “Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host. ” Since we will be out of the office for a week, we are setting your letter to post live on Saturday at noon.
Letter 36 – Tachinid Fly
Red Spiky Bee-Type Bug
January 22, 2010
We were hiking to Lower Calf Creek Falls between Escalante and Boulder, Utah last September, when we came across this strange looking bee-type bug. What is it?
Between Escalante and Boulder, Utah
What a gorgeous photo of a Tachinid Fly. It will probably take an expert to get a definitive positive species identification, but it does look quite similar to Macromya crocata, a species posted on BugGuide and photographed in nearby Arizona.
Letter 37 – Tachinid Fly
Bumble-sized white-faced bee-mimic fly. Botfly?
June 2, 2010
Saw several of these large bee-mimicing flies feeding on a flowering tree. Looked through 9 pages of bee mimics on WTB and didn’t anyone quite like it.
The bristly hairs on the back end seemed botfly-like to me, but google hasn’t turned up a winner there either.
Thanks for your help,
This is a Tachinid Fly, Belvosia borealis, and we matched it quickly to a photo on BugGuide. According to BugGuide: “Larval stages are parasitoids of other insects. Almost every order of insects is attacked by tachinids, including a few types of non-insect arthropods. Some tachinids are very specific and others can parasitize a wide variety of hosts. The most common hosts are caterpillars.” BugGuide also indicates: “Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.“
Their hosts would have to be something pretty meaty considering the size of the fly, will keep an eye on that tree this season and see what else grows there.
Thanks very much.
Letter 38 – Tachinid Fly
What is it
Location: Jerome, AZ
August 10, 2010 8:07 am
I think this was summer time, Mingus Mtn, near Jerome, AZ.
Would like to know what to name this thing.
This fly is a Tachinid Fly in the family Tachinidae. According to BugGuide: “Larval stages are parasitoids of other insects. Almost every order of insects is attacked by tachinids, including a few types of non-insect arthropods. Some tachinids are very specific and others can parasitize a wide variety of hosts. The most common hosts are caterpillars.” BugGuide also indicates: “Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.” Finally, in terms of species identification BugGuide advises: “Bristle placements, facial conformation, and antennal shapes are helpful in identifying genera; images that show these features have a better chance of being identified.” Sadly, we do not feel confident taking this identification to the species level and believe that might require a dipterist who specialized in flies.
Species identification courtesy of Eric Eaton
Went through the site and found only a few minor corrections/clarifications, most recent to oldest:
Tachnid fly from Jerome, Arizona: Paradejeania rutilioides …
…Otherwise, either very good or “I can’t help with that:-)”
Is the book out for everybody yet? If so, I’ll link it to my blog, share on Facebook, etc. I did get the pre-order e-mail from you.
The book will be available in October.
Letter 39 – Tachinid Fly
Re: SUBMISSION: What insects are on this caterpillar? – – 04/29/10
August 16, 2010
All I know about “insects” is that they annoy me, BUT I have an insatiable sense of curiosity and respect for Nature (and a Nikon Micro lens), SO thought I’d run this one past ya. Is this a species of fly that is naturally hypomelanistic OR is it some albino variant? SEE 2 images ATTACHED
Tore out my entire front porch the other day trying to capture a centipede from Mars. I’m here in the Hill Country of Texas, so we see all manner of stinging inverts, but this one was the mother of all mothers. She was HUGE. I had 12″ dressing forceps on her twice, but was afraid of hurting her – to the point of losing her. Better for her to be lose and intact than smishes, eh? I’ve captured dozens of them around here, but this was 50% larger than any before. I got eggs from some Central American centipedes twice, and this one reminded me of one of those (smaller, of course).
South Mountain Reptiles
Hi again Don,
The circuitous way you sent in this email, by responding to an older correspondence rather than by using our standard form, sent us off on a mission while working on your post. First, we believed this fly looked like a Tachinid Fly (see BugGuide), a group of parasitoid flies that prey upon caterpillars among other insects. We found a fly on BugGuide in the genus Ornia that seems to bear an uncanny resemblance to your fly, but alas, BugGuide has no information on the genus, though there is data that it has been reported from across the continental U.S. Now we wonder if perhaps this is the adult of the unidentified fly larvae that had parasitized the Underwing Caterpillar you submitted back in April and you subsequently used to submit this identification request. You may have unwittingly provided an answer to your previous request. We will check with Eric Eaton to get his opinion on both this identification and our supposition on the previous identification request.
Eric Eaton responds
August 18, 2010
I don’t know. Ormia are parasites of crickets, though, not caterpillars. I can’t draw any conclusions on this entire thing. Tachinids are certainly not my specialty. Sorry.
August 17, 2010
I’m sorry I didn’t submit per the usual channel. It was late last night (this am), and my son brought it to me. He’s not into animals per say, but has been around me enough to “wonder” when he sees something odd. Since 100% of all the flies the average person sees in his/her life are black, seeing this one made him bring it to me. Unfortunately, while I was resizing the pix, he turned it loose. Like me, unless it’s one of our unwanted neighbors (L. reclusa), he prefers to see the animal released where they were found. I’m proud of him for that, but wish I’d caught him before releasing that one. Somebody may have wanted it for closer examination. IF we see another, I’ll do something to make it ship-worthy in a hurry. I’m a certified reptile shipper with Fed Ex, so I can get one from point A to point B in a hurry without raising eyebrows (in the event it’s a potential bio-polutant).
Thank you for your response,
South Mountain Reptiles
August 20, 2010
Thank you SO much for inquiring. It’s wonderful to know that there are so many inverts on our special planet that it’s can still be difficult to find experts for each of them.
Letter 40 – Tachinid Fly
What is this bug?
Location: Cloudcroft Observatory, New Mexico.
September 10, 2010 4:11 pm
Hello. I was curious about a bug I saw in the mountains at Cloudcroft, New Mexico. This bug was found at the Cloudcroft Observatory. It seemed a lot like a bee because it buzzed, but it looked totally different than one.
This bug was seen in August, 2010.
The color palette of your photograph is so beautiful. This is a Tachinid Fly, probably Adejeania vexatrix based on images posted to BugGuide. Adult Tachinid Flies take nectar from flowers, but immature larvae are endoparasites on a variety of insects and arthropods, often limiting themselves to a single species.
Letter 41 – Tachinid Fly
Location: New Jersey USA
September 11, 2010 5:13 pm
Your Tachinid Fly resembles this unidentified species on BugGuide.
It probably is mine and the same. I was not able to get an ID for the fly. Thank you for your mail
Letter 42 – Tachinid Fly
Location: Eastern Ontario, Canada
September 7, 2010 3:03 pm
Can you please help me identify this insect that appears to have 4 eyes. i have never seen anything quite like this anywhere. was very friendly during vacation near Kingston Ontario. We named it the Raspberry Fly because of its colour and approximate size being close to a raspberry. the picture attached is cropped. It is sitting on a friends palm.
September 20, 2010 11:30 am
good afternoon, I understand your staff is small, i was just wondering what the screening process is. I sent in a picture of an insect I and anyone I show the picture to has never seen before. the title was “Strange Fly” (September 7th, 2010) I was hoping to send friends links to you site to see the bug.
A name is much nicer than the interrogative punctuation mark you used on your original request. We apologize for never responding to your original request, but as you indicated, we do have a small staff. One person, The Bugman, responds to as many letters each day as time not spent on the time clock teaching college classes allows, and then The Bugman posts selected letters to the internet. A second staff member oversees the running of the website, ensuring that the web browsing public has the highest quality service that our means permit. This fly is a Tachinid Fly, possibly Hystricia abrupta, which you may see on BugGuide. This group of Tachinid Flies are parasitoids on caterpillars. Here is the explanation posted to BugGuide: “The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
P.S. There are currently 9473 letters in our email inbox.
Wow, some hobby! Thanks so much for your attention in this matter.
I apologize for seeming terribly impatient.
Your help is very much appreciated.
Have a great day.
Letter 43 – Tachinid Fly
Location: Asheville, NC
September 8, 2011 8:22 pm
I saw this hairy fly in Asheville, NC last August. The fly has an orange abdomen with black stripes and large stiff-looking black hairs. It is about an inch long. I would love to know what it is!
Thank you for your help.
This fly is a member of the family Tachinidae, and they are commonly called Tachinid Flies, a name that is basically just a reference to the family. We haven’t the necessary skills to identify the species. Here is what BugGuide has to say about this large family of parasitoids: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 44 – Tachinid Fly
Subject: flies? bees?
Location: central Wisconsin
July 11, 2012 8:39 pm
At first I thought they were bees, many of them going from flower to flower. But faster, and more skittish. They look like flies, but what flies go to flowers?
This is a Tachinid Fly, but we cannot be certain of the species because it is a very large family and many members of the family look similar. Your individual looks very much like this Tachinid Fly image we posted earlier in the week. Tachinid Flies are very important components in the food chain. They are parasitic flies that often target a single host in the insect and arthropod world. Many Tachinid Flies prey upon caterpillars and true bugs. It is the larva that is the carnivore and the female Tachinid Fly lays an egg on the host creature. The egg hatches and the larva begins to feed on the internal tissues of the host, eating it alive, eventually killing it. Many adult Tachinid Flies are pollinators that feed on nectar and pollen from blossoms, but Tachinid Flies are not the only Flies that go to flowers. Bee Flies, Hover Flies and Small Headed Flies are just a few of the families of flies that are important pollinators. You may have heard the old saying “You can attract more flies with honey than with vinegar” though sometimes “vinegar” is replaced with the more colorful slang term for excrement. Honey is nothing but the nectar of flowers that is gathered by bees. So to answer your question, many flies go to flowers.
Letter 45 – Tachinid Fly
Subject: Robber Fly?
Location: Baldwin Hills in Los Angeles, CA
July 20, 2012 11:56 am
Found this guy last week on a backyard window sill. S/he seemed a bit worn down. I’d guess length to be 3/4”.
I’ve pics of a larger yellow/black robber fly in the same area from last year, if you’re interested.
This brown one is smaller but reminiscent of other robber flies I’ve seen on your site.
Thanks for all your great work and insights.
This is not a Horse Fly. It is a Tachinid Fly, a member of a family of flies that parasitize other insects and arthropods. This is a large, diverse and confusing family, and we did not know if we would have much luck with a genus or species identity, but the white face seems rather distinctive. Upon doing a web search, we found this very similar photo on Bugguide, and we suspect your fly is probably in the same genus, Gonia. BugGuide has this photo of a genus member from California.
Letter 46 – Tachinid Fly
Subject: Some kind of fly?
Location: Bonnyville, Alberta, Canada
July 12, 2013 2:59 pm
I found this flying around my vegetable garden today and have not been even close to finding a similar kind online. Hopefully you have an idea? I live in Bonnyville, Alberta, Canada. It was taken on July 12, 2013 in the summer time, although it was a really windy and abnormally cool day of only 15 degrees Celsius today.
Signature: Weird garden bug!!! Guaranteed you’ve never seen one!
This is a Tachinid Fly, and it might possibly be Hystricia abrupta, which you may see on BugGuide. Tachinid Flies are parasitoids, meaning they lay eggs on other insects and arthropods, and the developing larvae eventually kill the host. Many Tachinid Flies are parasitoids of caterpillars.
Letter 47 – Tachinid Fly
Subject: Bee Fly?
Location: Northern Arizona, Flagstaff
September 10, 2013 8:27 pm
I photographed a rather large two winged fly on my Butterfly Bush in Flagstaff Az.
This is the high desert, 7, 000 feet above sea level.
Low humidity, day time highs around 70,
50 at night.
We get snow in the winter months.
The abdomen is bright orange in color and rather stunning.
They have large fly eyes unlike bees.
R.A in Flagstaff
This is a Tachinid Fly, an important family of parasitoid insects. We posted a similar looking Tachinid Fly from the mountains of New Mexico that we featured as a Bug of the Month and tentatively identified as Adejeania vexatrix.
Letter 48 – Tachinid Fly
Subject: What the heck is this?
Location: Creede Colorado
August 4, 2014 7:11 pm
I took this picture a few days ago about 30 miles west of Creede, Colorado. Would love to know what this thing is called.
Signature: P Padgham
Dear P Padgham,
This is a Tachinid Fly, a member of an important family of parasitic flies that prey upon insects and arthropods. Many Tachinid Flies are valuable biological control agents for agricultural pests. Many Tachinid Flies look very similar and they are quite spiny.
Letter 49 – Tachinid Fly
Subject: What is it?
Location: Oceanside, NY
August 19, 2014 8:20 pm
Don’t have a clue. This bug, feasting on Japanese Knotweed, could be a bee, a fly or even a moth, as far as I know…..
This is a beneficial, parasitic Tachinid Fly, but we cannot tell you the exact species at this time. Tachinid Flies are often very host specific and they are often important biological control agents that parasitize other insects and arthropods.
Letter 50 – Tachinid Fly
Subject: Fly on calico asters
Location: Kent County, Michigan USA
September 21, 2014 3:57 pm
What is the name of this cool fly I found enjoying calico asters in Michigan in late September? Thanks!
This is a Tachinid Fly in the family Tachinidae, but we are not certain of the species. Tachinid Flies are parasitic on other insects and arthropods. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 51 – Tachinid Fly
Location: Mogollon Rim near Payson AZ
July 31, 2016 11:03 am
I found this colorful insect on a flower in the Tonto National Forest in Eastern Arizona July 30, 2016.
We were hiking along the Mogollon rim at an elevation of 5,000 feet.
Thanks for your help!
Signature: Ann in Arizona
This Tachinid Fly in the family Tachinidae might be Macromya crocata based on this BugGuide image, though there are many other members of the family that look quite similar. Another possibility is that this might be Adejeania vexatrix which according to BugGuide: “Bristles concentrated in rings adjacent to the joints between abdominal segments. In the strikingly similar Hystricia abrupta, the bristles are scattered across the surface of the abdomen.”
Letter 52 – Tachinid Fly
Subject: Strange bee faced fly
Location: Nashville, TN
May 11, 2017 12:25 pm
My mother and I were sitting on our front porch and noticed this insect flying around. It landed a few times and stayed still for a good length of time each time without moving so I got a few decent pics. It’s furry and black and has what looks like the face of a bee. Every year I feel like I see an insect that I’ve never seen before. This is the one for this year so far:
Signature: Any info would be appreciated, Nora
This is some species of Tachinid Fly, and members of its family are all beneficial predators that parasitize a variety of host creatures that helps in population control. Sometimes a species of Tachinid Fly is the only known predator of a significant agricultural pest species. This BugGuide image is similar to the image you provided, though we cannot confirm that they are the same genus or species.
Letter 53 – Tachinid Fly
Subject: Orange hairy butt fly
Location: Central NY, south of Ithaca
July 31, 2017 7:53 am
I was intrigued by this fly whilst walking my dog early one morning in late July. It was relatively slow moving and stuck around the same plant for a few minutes. It was the size of a large housefly. I encountered it on a mowed walking path near some grain fields at the edge of state forest land, in the Finger Lakes region of New York State. What is this delightful creature?
This is a parasitoid Tachinid Fly or Bristle Fly, but we are uncertain of the species as there are many similar looking species in this very large family.
Letter 54 – Tachinid Fly
Subject: Fly identification
Geographic location of the bug: Idaho
Time: 11:16 PM EDT
Dear Mr. Bugman,
I took a photo of a large, mostly black fly with two white dots on the rear part of its abdomen. I have only found the fly outside once. All other flies inside my house are plain black with no white dots. I have attempted to find the type of fly online but with no luck so far. If you know what type it is I’d be very interested to hear. Thank you for your time and help!
How you want your letter signed: Sincerely, Sarah
This is a parasitoid Tachinid Fly, and according to BugGuide, there are “1350 spp. in >300 genera of 4 subfamilies in our area [North America].” We quickly scanned BugGuide down to the tribe level and could not locate this particular species. Tachinid Flies are important biological control agents against other insects and arthropods, and according to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby.” If time permits, we will try to identify your Tachinid Fly to the species level, but now you also know where to do the research. If you find a visual match, please let us know.
Letter 55 – Tachinid Fly
Subject: Giant Tachinid Fly
Geographic location of the bug: Arlington, WA
Time: 02:13 PM EDT
I have two what looks like Giant Tachinid flies on my mint outside this week. I took a number of photos as it looked way different than any I’ve seen. It really looks like Giant, but according to all research I have found, its not located anywhere here .. only Europe and that region. Are there Giant species here? This was the size of a larger bumblebee.. so I noticed it at once.. stiff bristles on a smooth black body with orange head and wings.. so it stood out. Funny enough the photos I find are all in the UK on mint as well. Thank you for any clarification on this species.
How you want your letter signed: Sammy Catiis
Tachinid Fly is a name used for a member of the parasitoid family Tachinidae. According to BugGuide, a site dedicated to North American sightings: “Second largest dipteran family (after Tipulidae), with ~1350 spp. in >300 genera of 4 subfamilies in our area(1) and >10,000 spp. in ~1600 genera worldwide; it is possible that only half of the species have been described.” We searched for images of the Giant Tachinid Fly, and we found an image on Alamy from Wales that is identified as Tachina grossa and it has a light collar of hairs behind the head, a distinctive feature also found on your individual. The genus is also found in North America, and this BugGuide image also has the light collar. Data indicates the genus is found in Washington. Congratulations on identifying your individual to the genus level. According to BugGuide “40 spp. in 2 subgenera in our area” but most of the individuals posted to BugGuide are not identified to the species level, so we suspect they are difficult to identify from images.
Letter 56 – Tachinid Fly
Geographic location of the bug: Sanbernardino National Forest – southern California
Time: 09:39 AM EDT
What the heck is this?? Lol
Found in Southern California on a rabbit brush bush.. feeding on the blossoms. Nov 8, 2017
How you want your letter signed: Sandy
This is not a Bee Fly. It is a member of the family Tachinidae, and the only common name for members of the family is Tachinid Fly. According to BugGuide, it is the “Second largest dipteran family (after Tipulidae), with ~1350 spp. in >300 genera of 4 subfamilies in our area(1) and >10,000 spp. in ~1600 genera worldwide; it is possible that only half of the species have been described.” There are many genera that look similar, and the same with species, so we don’t believe we will be able to provide you with an exact species name, but it might be Paradejeania rutilioides which is pictured on BugGuide. There is a similar looking individual not identified beyond the family posted on the Natural History of Orange County site. Tachinid Flies are parasitoids, and the female lays an egg on a host that hatches and feeds on the internal organs of the host, eventually killing it. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 57 – Tachinid Fly
Subject: What is this? A horsefly? A bee? Or a hybrid maybe?
Geographic location of the bug: Huntsville, Texas
Time: 05:30 PM EDT
Hi. I found this at Sam Houston State University to be more specific. I’m not sure if it’s a bee or a fly, or even a new species. I’m in Forensics and our class needs to catch 20 bugs so that’s why it’s in two ziploc baggies. I was afraid it might bite or sting me through one bag. It looks sort of mean. While I don’t need to know, it would be cool if I knew what it is.
How you want your letter signed: Thank you, Sadie
Normally we do not feel compelled to provide identifications for class projects, but something about your request resonated with us. This is a parasitoid Tachinid Fly in the family Tachinidae, and this is a very large family with many similar looking species. We believe based on images posted to the Flies of Goodwell and Texhoma, Texas Co. OK site that it is in the tribe Blondeliini. BugGuide has four pages of genera in that tribe, so a more specific identification might require an expert in the family.
Letter 58 – Tachinid Fly
Subject: Strange looking housefly I saw in my garden
Geographic location of the bug: Kelowna, British Columbia
Time: 08:38 AM EDT
Your letter to the bugman: I took a photo of this fly I saw on a plant while I was weeding my flower garden on May 24th 2019. It looks like a cross between a housefly and a ladybug. I took several photos, but in the first one you can see the line of black dots on it’s red back.
How you want your letter signed: Samantha C.
This is a beneficial Tachinid Fly a member of a family of parasitoid flies with larvae that prey upon a variety of arthropods. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars.” We believe based on this BugGuide image, your individual is in the genus Gymnosoma. According to BugGuide: “Hosts are Pentatomidae bugs. Adults take nectar.” Pentatomidae includes Stink Bugs and Shield Bugs, many of which are agricultural pests. The Master Gardener Program of the University of Wisconsin-Madison has a nice page on Tachinid Flies.
Letter 59 – Tachinid Fly
Subject: Found a Belvosia
Geographic location of the bug: Burnham Maine, Waldo County
Time: 01:48 PM EDT
Your letter to the bugman: Finally I was pruning one of my flowering bushes and my daughter and I came across this huge fly but it looks like a bee I’m like it looks like a crossbreed between a fly and a bee and she said yeah it does so I looked it up because I have Google lens on my phone and it said it was a Belvosia and then I found some articles stating that they’ve also been sighted in Clinton and Fairfield Maine which I lived in Clinton too so I wanted to submit a few pictures that I took to you
How you want your letter signed: Bobbie Jean
Dear Bobbie Jean,
Congratulations on successfully identifying your Tachinid Fly in the genus Belvosia. Thank you also for submitting your excellent images. According to BugGuide they feed on Lepidoptera. The female Tachinid lays her eggs on a caterpillar and the fly larvae parasitize the caterpillar.
Letter 60 – Tachinid Fly, we believe
Subject: Interesting fly
Location: Northern Utah, Rocky Mountains, in a valley about half an hour away from The Salt Lake, and 10 minutes from a river, and 15 minutes from a reservoir that feeds the river
April 12, 2017 6:54 pm
This fly visited me early spring In Northern Utah. Physiologically, it looks nearly identical to a common housefly, with the same skittishness and “mouthing” behavior. The mouth was narrower but roughly the same shape as that of a housefly. It is slightly smaller than a housefly. My guess is a mutation, but insects are not my feild. Thank you for your time.
We believe this is a parasitoid Tachinid Fly, but we do not recognize the species. According to BugGuide: “Second largest dipteran family (after Tipulidae), with ~1350 spp. in >300 genera of 4 subfamilies in our area and >10,000 spp. in ~1600 genera worldwide; it is possible that only half of the species have been described.”
Letter 61 – Tachinid Fly emergence and possible Fungus from the UK
Subject: What is going on – two photos?
Location: Essex, UK
August 31, 2015 10:38 am
I photographed these at Thameside Nature Park on 30 August.
The fly appears to be sitting on a nest apparently containing tiny youngsters – and with a trapdoor at the end. Has the fly been caught and left as food for the youngsters? Is it eating them itself?
These is also this strange red thing which appears to be spinning itself a cacoon.
We believe this is a Tachinid Fly, a parasitoid, and we believe your image might have something to do with the adult Tachinid Fly emerging from its host insect. The other image might have something to do with fungus. This is all conjecture and we eagerly welcome any additional information.
Letter 62 – Tachinid Fly from Australia
Subject: Bristle Fly?
Geographic location of the bug: Mittagong NSW
Time: 10:42 PM EDT
Your letter to the bugman: Saw this today. Is it a Bristle Fly?
How you want your letter signed: Thanks and regards, Paul
This is a Tachinid Fly in the family Tachinidae, and members of this family are sometimes called Bristle Flies in Australia, but we are not entirely certain if that name is used for the entire family or just a few species, like Amphibolia vidua which is represented on our site under the common name Bristle Fly. We believe your individual is a different species, possibly Formosia speciosa, which is pictured on the Brisbane Insect site.
Letter 63 – Tachinid Fly from Australia
Subject: Bristle Fly
Geographic location of the bug: Oakdale NSW
Time: 06:58 PM EDT
Your letter to the bugman: Can you please confirm if the attached image is of a Bristle fly. The markings are slightly different than those on your website.
How you want your letter signed: Bristle fly?
This is a Tachinid Fly in the family Tachinidae, and some species are known as Bristle Flies because of the course hairs that cover the abdomen of many species. We believe your individual might be Formosia speciosa which is pictured on Brisbane Insects.
Letter 64 – Tachinid Fly from Costa Rica
January 31, 2010
I spent a while trying to get a good shot of this fly that was warming itself in Costa Rica. Any idea what it is? It was about twice the size of a common housefly.
Santa Elena cloud forest, Costa Rica
As we said in a previously email to you, often exact species identification of tropical species is quite difficult with online resources, and an expert in the family would be necessary. With that said, we are relatively certain that this is a Tachinid Fly in the family Tachinidae. Tachinid Flies are internal parasites whose hosts are a variety of insects and other arthropods. Caterpillars are the most common hosts.
Letter 65 – Tachinid Fly from Ecuador
Bee Fly from Ecuador
Location: Quito, Ecuador
January 15, 2011 1:44 am
I photographed this insect just outside Quito, Ecuador, on 2-Nov-10. I believe it to be a Bee Fly but know almost nothing about inscts of Ecuador. Can anyone help with identification?
In our opinion, this is a Tachinid Fly in the family Tachinidae. According to BugGuide, a website dedicated to North American species: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.“
Letter 66 – Tachinid Fly from the UK
Subject: Unusually large fly
Geographic location of the bug: South Wales
Time: 09:12 AM EDT
Your letter to the bugman: Hi there, a very unusually large fly came into my kitchen which I have trapped in a vase alongside a British pound coin to give perspective. I live in a rural location, about 900feet above sea level, there are sheep, cows and horses roaming nearby and it’s an unusually hot summer. Are you able to let me know what this is please?
How you want your letter signed: Kathryn
This is a beneficial, parasitoid Tachinid Fly in the family Tachinidae, a very large and diverse family, and it appears to have a lighter, yellow head, which causes us to believe it is Tachinia grossa. See Diptera Info for an image of that species. Parasitoid insects lay eggs on or near other insects, arthropods, and occasionally other creatures, and when the larvae hatch, they feed on the host. Many Tachinid Flies prey upon caterpillars, and NBN Atlas includes a list of known caterpillars preyed upon by Tachinia grossa, including the Oak Egger or Lasiocampa quercus, the Gypsy Moth or Lymantria dispar and Hemaris fuciformis, a diurnal Hawkmoth.
Letter 67 – Tachinid Fly with Fungus Infection
Subject: Another example of Tachinid Fly with Fungus Infection??
Location: Birmingham, United Kingdom
October 6, 2014 3:21 am
I think this is another example (found 6th October 2014) of a Tachinid Fly with the pathogenic fungus Enthomphthora Muscae, it just looks as if it flew straight into my back door and died on impact. Possibly the same as on your web page: 2009/12/25/tachinid-fly-we-believe/
Can you please confirm that it is a Tachinid Fly? As I don’t believe there are any ‘natural’ black and white stripped fly’s here in the UK that look like this one.
Signature: Milly – Birmingham (UK)
We agree with both your identification and your diagnosis. As Karl indicated in the link you provided: “There are numerous photos on the internet that look very similar to this this. The white banding occurs as the fungus bursts out between the abdominal segments (presumably just before the victim expires).”
Letter 68 – Tachinid Fly Pupae
We just got home from a ten day vacation. We have been keeping a cocoon that we found a few weeks ago so the kids can watch it develop. When we got home there are these black small larvae of some kind in the jar. Do you know what they are? How did they get in there? We have very small holes in the jar and it is in our house. Thanks if you can help us
We believe these are Tachinid Fly Pupae. Tachinid Fly larvae are internal parasites on many kinds of insects and arthropods, and they are often species specific. Caterpillars are a favorite host. We are presuming the female fly laid her eggs inside the caterpillar before it formed a cocoon and the young flies fed on the internal organs.
Letter 69 – Tachinid Fly from South Africa
Subject: What type of bug is this?
Location: South Africa
July 10, 2016 10:46 am
Please can you identify what bug this is?
Signature: Cherise Walker
This is a Bristle Fly or Tachinid Fly in the family Tachinidae, a group of parasitoid species that prey upon a variety of creatures. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally.” This individual on iSpot looks similar to your individual.
Letter 70 – Tachinid Fly from South Africa
Subject: Fly species?
Geographic location of the bug: Creighton, KZN, South Africa
Time: 10:21 AM EDT
Found this indoors, looks like a fly, but never seen this one before.
Thought it was Rhachoepalpus immaculatus, but coloring not the same.
How you want your letter signed: Terence
This is a parasitoid Tachinid Fly. According to Animal Diversity Web, Rhachoepalpus immaculatus is a Tachinid Fly. Tachinidae is a large family with many similar looking individuals, so we cannot say for certain if your identification is correct to the species level, but you do have the family correct.
Thanks for the prompt responce.
Letter 71 – Tachinid Fly: Uramya indita
A Fly in Southeast Arizona
August 4, 2009
I was wondering if you can Id this for me…it’s a colourful fly with patterned wings. They seemed not to be bothered at all when we get near them. They are congregating on our glass doors in our building this past month. They came and went and only stuck around for a few weeks. I think it could be some sort of Syrphid fly or a bee fly, but it’s just my guess. 🙂 I’m more into beetles and butterflies. Please help! Thank you! 🙂
When flies are this hairy, it is a very good indication that they might be Tachinid Flies. We browsed through the archives of BugGuide and identified your Tachinid Fly as Uramya indita, which has no common name. There is no species information, nor genus information, but on the subfamily Dexiinae page, BugGuide indicates: “Nearly all members of this subfamily are said to be parasitic on Coleoptera or Lepidoptera larvae.“ The Tachinidae family page of BugGuide indicates: “Food Larval stages are parasitoids of other insects. Almost every order of insects is attacked by tachinids, including a few types of non-insect arthropods. Some tachinids are very specific and others can parasitize a wide variety of hosts. The most common hosts are caterpillars. Life Cycle Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. When fully developed it leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Letter 72 – Tachinid Fly from Uruguay
Subject: I think it is a fly
December 5, 2016 10:37 am
Greeting, last year I sent in a request and you were very helpful in identifying a bug for me, thank you for that!
On my walk this morning I saw what I thought were a few sick-looking bees so I snapped some photos. Looking at the pictures when I got inside however they look more fly-like to my untrained eye. Either way their bodies appear swollen and weird.
The only specimens I have seen are on these plants that attract mostly flies, bees, wasps, hornets, and beetles. It is mid-spring now and I have just noticed them for the 1st time this morning. The pictures attached are front, back, and top-down respectively. Thanks!
You are correct that this is a Fly. More specifically, it is a Tachinid Fly in the family Tachinidae, a family whose members are parasitic. According to BugGuide: “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”
Thanks again! You guys really know your stuff.
Letter 73 – Tachnid Fly
HUGE fly (not a cicada or bumble bee!)
Hi Bug Man,
I1ve lived all my life in the SF Bay Area but have never seen a fly this large (about 1 inch). I1d love to know what it is – any clues? Thank you!
What a funny photo. This is a Tachnid Fly. They are important biological control agents since they parasitize caterpillars. There are several genuses in the subfamily Tachinae pictured on BugGuide, and we are not sure if your specimen is in the genus, Adejeania, Hystricia, Paradejeania, Protodejeania or some other.
Letter 74 – Tachnid Fly
Is this a drone fly? This specimen was resting on a garden bench in early spring at my home on southern vancouver island, BC. Thanks to your site, I also would like to report a successful id of a Bedstraw Hawkmoth (Celerio galii) (see sphinx moths 2 – (05/14/2006)) that I found beside the side of the road near Banff National Park in the Canadian Rockies. For your interest I have attached a closeup photo of its head. It has amazing eyes!!
The fly you sent is not a Drone Fly, but a Tachnid Fly, probably Gymnosoma fulginosa, according to BugGuide. Adults are nectar feeders and larvae are parasitic on True Bugs and Beetles. Eggs are laid inside the host and the larvae feed on internal organs. Tachnids are important biological control agents.
Letter 75 – Two Native Bees and a Beelike Tachnid Fly
Can you please help me identify some mystery pollinators
I really appreciate your site and the information that you share, your photos and descriptions have helped me identify several mystery insects, including sweat bees, hover flies and bee killers, and I’m hopping that you might be able to help me identify a few more. I have attached three photographs of separate insects, all of which appear to be pollinators which I have found in my yard. I have recently taken an interest into native pollinators since I have taken up the hobby of beekeeping. I truly admire the labor of these critters, I just wish I could identify them by name. I think I know the identity of two of my submissions, I believe one to be a ‘blue orchard mason bee’, and the other I think is a photograph of two separate ‘leaf cutter bees’, perhapses alfalfa leaf cutters. Both of these apparently solitary insects last spring and summer had taken to laying eggs in a nesting block I installed in my garden.
|Leafcutter Bee||Orchard Mason Bee|
The last picture is of a critter that has me confused as to it’s true identity. This bumble bee sized fly-like creature is pictured on a stevia plant (aka sugar herb), but seems to also like holly and basil flowers, they however completely avoid catnip in bloom, which is odd as it seems to attract every other pollinator I’ve seen in my yard. They seem to be particularly prevalent around my beehive, though this may simply be coincidence. Can you help me identify this last specimen, and confirm my beliefs on the previous too? Any help that you could lend would be much appreciated.
We will post your images of the Orchard Mason Bee and Leafcutter Bee and see if we can get an exact species names for you. Meanwhile, your mystery pollinator is a Beelike Tachnid Fly, Bombyliopsis abrupta. The adults drink nectar, and the larvae are internal parasites on caterpillars.
Update From Eric Eaton
“Yes, the left one is a female Megachile sp., though not the one he thought it was. The right one is a male Osmia sp., no telling which one from the image alone. Both are very nice images. Eric”
Letter 76 – Owl Butterfly Caterpillar with Tachinid Fly Eggs from Costa Rica
Subject: I named him Ryno
Location: Costa rica Jungle
April 27, 2013 5:07 pm
This is a little friend I found deep in the Jungle in Costa Rica. Anyone who what he is?
We do not recognize this unusual looking caterpillar. Generally Butterfly Caterpillars are not hairy, but we suspect this might be a Nymphalid Caterpillar.
Keith Wolfe responds to our identification request
Greetings “Ryno” and Daniel, this is a last-instar Caligo atreus (http://janzen.sas.upenn.edu/caterpillars/dblinks/searchplaycat4.lasso?-Search=GCAcaterpillars337&herbivore%20species=atreus). Note the numerous white tachinid (http://www.nadsdiptera.org/Tach/Gen/tachintr.htm) eggs behind the head capsule, the inevitable doom of which it might possibly escape if pupation occurs before the maggots hatch.
Thanks for getting back to us on this. We didn’t realize those were Tachinid Fly eggs. Good to know. We hope this Owl Butterfly Caterpillar escapes being eaten alive by the fly larvae.
Letter 77 – Unknown Cricket Parasite is a Tachinid Fly, Ormia ochracea
Eerie Cricket Thingy
Sat, Nov 8, 2008 at 11:07 AM
Yesterday a mysterious reddish-brown pill shaped object suddenly began emerging from the underside of one of our pet crickets. Looks like some sort of egg, but from what we can tell, cricket eggs don’t look like this. The cricket seemed healthy before this emerged, and was alive for a while when it first appeared, but now is dead. Could it be that some other insect such as a wasp laid its eggs inside the cricket as a host? I’ve heard of them doing this to caterpillars, but crickets? Or is it something else?
Paul and Stella
Hi Paul and Stella,
This is a new one for us and we will need to do some research. We will also try to contact Eric Eaton to see if he has an opinion. We, like you, suspect this is some type of internal parasite that has had its meal and is perhaps pupating outside the cricket’s body. It would be interesting to see what, if anything, eventually emerges. If we were betting, we would bet on a Tachinid Fly. Moments after we posted, we found an online article on a Tachinid Fly, Ormia ochracea, that parasitizes crickets.
The object protruding from the deceased cricket is indeed a fly puparium (the rigid last larval ‘skin’ enclosing a fly pupa). It could certainly be a tachinid fly, but there are also other flies that are parasitic on crickets, especially some members of the flesh fly family (Sarcophagidae). I’d personally be hard-pressed to identify even the adult fly once it emerges, though a dipterist (fly expert) could.
Update: November 18, 2012
Thanks to a comment just made by a reader with experience in Tachinid Flies, we are confident to report that this pupa belongs to the Tachinid Fly Ormia ochracea. This Cornell University article tells the fascinating account of this Tachinid Fly that uses sound to locate its host when the male Crickets call to attract females.
Letter 78 – Veined Ctunecha 1000 miles off course, and Tachinid Fly
Blue Bug with Orange Head
Wed, Jun 24, 2009 at 5:00 PM
Found this flying through my garage tonight at sunset in southern Ontario, Canada. Wrongly identified it quickly on the net as a Pine False Webworm, but the wings clearly indicate that it is something else. 2nd one I’ve seen in the area in 2 days and am wondering if there is an invasive species to be concerned about.
We are a bit puzzled by your specimen, so we are contacting Julian Donahue, a specialist in the Arctiid Moths. This looks like a member of the genus Ctenucha (pronounced “ten U ka”) but BugGuide only list the Virginia Ctenucha, Ctenucha virginica from your area. It more closely resembles the Veined Ctenucha, Ctenucha venosa, but the Butterflies and Moths of North America lists its range as being nearly 1000 miles south and west of Ontario. Hopefully, Julian will give us a prompt reply. The fly in your one photo is a Spiny Tachinid Fly, Paradejeania rutilioides. According to BugGuide, adults take nectar and larvae are internal parasites of Tiger Moth Caterpillars.
Expert Comment from Julian Donahue
It’s Ctenucha venosa, alright, a species of the Southwest and Mexico.
Are you sure it’s from Ontario, Canada, and not Ontario, California (I don’t know of any California records, but it is more likely to have been accidentally imported here than to Canada).
If it is really from Canada, pass the photo and details on to Dr. Don Lafontaine, the noctuoid specialist at the Canadian National Collection in Ottawa–he would be greatly interested in Canadian records of this species.
Could it be that this unusual sighting is yet another sign of global warming?????
More Expert Commentary
Hi Daniel & Jason –
As Julian points out, this is definitely a noteworthy record if it is from Ontario; the nearest documented records of venosa are from northeastern Kansas. Since this conspicuous species is not known to occur between Kansas and Ontario, where the fauna is quite well-known, it is highly unlikely that this is a natural range expansion as might be the case with ‘global warming’; it more likely represents an accidental introduction by way of plant material (the larvae feed on grasses and sedges). I occasionally identify C. virginica cocoons attached to shipped nusrsery plants – this may be a similar case.
Jason, since this would be the first documented record of this species for Canada and well outside its known range, could you please provide me with the exact locality and date? Even better would be one or more specimens sent here, also with collecting data – I can give you more info if you are able to do this.
PS – the tachinid fly in the photo is Hystricia abrupta, a widespread species in northeastern North America; Paradejeania rutilioides is a much larger, differently patterned species that occurs in the southwestern US
B. Christian Schmidt, Ph.D.
Entomologist, Canadian Food Inspection Agency
Canadian National Collection of Insects, Arachnids & Nematodes/.
Letter 79 – Tachinid Fly and Hover Fly from United Kingdom
Please I.D. this fly for me
January 7, 2010
these photos were taken on the 4th July 2009 at the side a track which runs along side a woodland which is within the very large area of Britains largest lowland raised bog area called Thorne Moor in South Yorkshire.The weather was warm still and sunny at the time
South Yorkshire, England, U.K.
We have been obsessed with trying to identify your magnificent black fly with a golden head, but alas, we have had no luck. The Bioimages website Diptera page is rather difficult to search for images and it proved fruitless. www.gwydir.cemon.co.uk is a nice website with numerous photos of flies, but again, your distinctive fly is not represented. We believe this is a Tachinid Fly in the family Tachinidae. We would not rule out a Bee Fly in the family Bombyliidae, or it may even be in some other family. We have finally decided to post your photos and request assistance from our readership and we will also be writing to Eric Eaton to see if he can at least provide the family.
We believe the third photo you submitted is of a different species since the wing pattern is different.
Eric Eaton provides an identification
Yes, this is definitely a large tachinid fly, Family Tachinidae, maybe Tachinia grossa. The third image is of the backside of a different fly, and that one is a flower fly (Syrphidae), specifically Volucella pellucens.
Letter 80 – Tachinid Fly
Subject: Unidentified fly
Geographic location of the bug: North Carolina
Time: 08:19 PM EDT
Your letter to the bugman: This was on my door in spring. Never seen one before.
How you want your letter signed: Charlotte
Our best guess upon first viewing your image is that this might be a Long Legged Fly in the family Dolichopodidae, but we could not conclusively find any matching images on BugGuide. It also somewhat resembles this Root Maggot Fly in the family Anthomyiidae pictured on BugGuide. We hope one of our readers will be able to assist with this identification.
Update: April 21, 2018
Thanks so much to Cesar Crash of Insetologia who provided us a link to the Tachinid Fly Cholomyia inaequipes that is pictured on BugGuide. According to BugGuide: “Females seen on flowers, perhaps (?) taking nectar” and “Parasitoid of weevils (Conotrachelus). Males, at least, come to lights.” We believe the submitted image is of a male and since it was found on a door handle, it might have been attracted by the porch light.
Letter 81 – Tachinid Fly from Australia
Subject: Strange beefly
Geographic location of the bug: Mount Helen
Time: 01:47 AM EDT
Your letter to the bugman: So, I had just got home and went to check the letter box when I saw this fly sitting on it. But it wasn’t just any fly! It had a strange pattern, opposite to a wasp’s and it had oval eyes, it also had a strange antenna that split into two at the end, it’s wings were a strange shape and were covered with orange and black fur. It had no stinger bus was similar in colours to a bee. And also it’s legs were slim but it’s body was wider. It didn’t move no matter how close I put my camera, which is ver strange. I’ve never seen a fly with thick fur, let alone an orange a black one! Please help me discover what this strange insect is, but also, it could be new!
How you want your letter signed: From Bethany
We are presuming you are from Mount Helen, Montana. We are feeling confident that this is a parasitoid Tachinid Fly, but we have not had any luck identifying it to the genus or species level. According to BugGuide: “Second largest dipteran family (after Tipulidae), with ~1350 spp. in >300 genera of 4 subfamilies in our area.”
Actually I’m in Mt Helen, Victoria. Is it possible that the fly is a new species?
Thanks for getting back to us, clarifying the original vague location information you provided for us. Now that we have established your actual location, we have located this image on Diptera Info that is identified as ” Tachinidae – Microtropesa sp. from western Australia.” We have another member of the genus Microtropesa among the postings in our archives. The genus is well represented on Atlas of Living Australia.
Thank you for the clarification, it looks a lot like what I saw
Letter 82 – Wasp: Tachytes species
Hi Bugman…looking for some help on this one. Been trying to identify this bee for the past two weeks but no luck. I cant find anything with those gold coloured eyes. I thought maybe it could be from the fly family but no luck there either. Thanks for your help!
Brantford, Ont. Canada
Maybe, just maybe, this is a Soldier Fly in the family Stratiomyidae, but there is not match on BugGuide. We are hoping Eric Eaton can assist with this beauty. Eric wrote in with this information: “It is actually a wasp, genus Tachytes, family Sphecidae. The females paralyze acridid grasshoppers as food for their offspring. Eric”