Currently viewing the category: "Tachinid Flies"
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Wasp Moth?
Hello Bugman:
I live in the Williamsport, Pennsylvania area. Here are some photos of a bug I have taken in the past few days. He is seen feeding on the goldenrod amongst many other bees and wasps. It is a little over an inch long. I can’t tell if it is a bee, wasp, moth or some combination. Any help would be appreciated.

Hi Alex,
This beauty is a Feather Legged Fly, Trichopoda pennipes, one of the Tachinid Flies. According to BugGuide: “Adult female lays one to several eggs on a hemipteran host. The larvae hatch from the eggs and burrow directly into the bug’s body, though only one larva will survive within each host. The larva feeds on the host internally and eventually a large cream-colored maggot exits from body of the bug (which soon dies). The maggot pupates in a dark reddish-brown puparium in the soil and emerges as an adult about two weeks later. There are up to three generations a year depending on location, and larvae may overwinter in the bodies of overwintering hosts.” and “Often used as biological control of hemipteran pest species such as squash bugs, stink bugs, and plant bugs. May hover above squash plants in search of prey.” The black tipped abdomen is a signal that this is a female fly.

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Monarch Bodysnatchers
Hello, Bugman,
I recently placed 2 large monarch caterpillars in an terrarium with some milkweed, so I could watch them go through metamorphosis. All was well… at first. One morning, I found one of the caterpillars hanging from under a branch, as though ready to pupate, but it was dead, shriveled, and and clear strands hanging from it. There were two small, yellow maggots in the tank, as well as a red pupa. After a bit of searching, I found this site /research/PNE/creasey.aspx . Apparently, an introduced tachinid fly, Lespesia archippivora, was brought over to control cutworms, but attacks non-target species like monarchs as well. Fortunately, the other caterpillar seems to have dodged the bullet, and has formed a lovely chrysalis. Regards,

Monarch CaterpillarMonarch Chrysalis

Hi Emily,
Thank you for your wonderful letter, excellent photos, precise documentation, and technical research. Though we approve of biological control methods over pesticides, we always question the introduction of biological agents before the total ramifications of the actions are made apparent.

Parasitized Monarch CaterpillarTachinid Fly larvae and pupa
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What is it?
Found by a friend in her garden in cygnet, AR Australia
Dee Stephen

Hi Dee,
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.  

What's That Bug? does not endorse extermination

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!

Hi Suzanne,
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.

What's That Bug? does not endorse extermination

drone fly?
Hi there,
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!!
Ian Mackenzie,
Victoria, BC.

Hi Ian,
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.

What's That Bug? does not endorse extermination

Can you please help me identify some mystery pollinators
Dear Bugman,
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.
Robert Engelhardt

Hi Robert,
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”

What's That Bug? does not endorse extermination