Snake flies might look like snakes, but they are harmless insects that help remove pests from your garden. But are their larvae equally harmless? Do snakefly larvae bite? Let’s find out.
There are more than 200 species of snakeflies worldwide, out of which you might find about 25 in North America.
In their larval form, These insects look like tiny snakes, which is why many people are afraid of them.
But the good thing is that snakeflies are not harmful at all to humans.
In fact, they eat up many common garden pests and insect eggs, which makes them beneficial for humans.
Moreover, they don’t usually bite anyone, so there’s really nothing to be afraid of. On some rare occasions, snakefly larvae may bite human skin, but it’s not dangerous in any way.
Read on to learn more about these fascinating creatures, their lifecycle, and what happens when they bite.
What Do They Look Like?
Snakeflies have an elongated prothorax, which makes them look like a snake. That’s where their unique name comes from.
It gives the impression that they are about to strike whenever they raise their heads, just like a snake’s hood.
These creatures are about ½ inch long and have two pairs of membranous wings, similar to those of lacewings. The transparent wings have a beautiful network of veins.
The head and wings of the snakefly are quite large compared to the rest of the body.
If you want to tell a female firefly from her male counterpart, the former comes with a needle-like ovipositor used to lay eggs in tree bark or soil.
What do the larvae look like?
The snakefly larvae are ½ to ¾ inch long and are soft-bodied creatures. They have six sticky legs, which help them move both forward and backward. This unique trait helps them catch their prey easily.
Do Snakeflies Bite?
No, snakeflies are harmless to humans and usually do not bite. The adult female snakefly has an ovipositor that humans may confuse as a stinger.
But this body part is only used as a tube to deposit eggs into tree barks or soil after piercing their outer shell and has nothing to do with stinging or biting.
Do Their Larvae Bite?
While adult snake flies do not bite humans, their larvae do. In some cases, people have got painful bites from the larvae.
However, these bites are not something that you need to worry about. At best, they can leave behind a rash for a few days.
The life cycle of the snakefly takes place in 4 stages:
- Egg stage
- Larval stage
- Pupal stage
- Adult stage
Let’s discuss each stage in more detail.
The first stage begins after the adult female lays eggs in the bark of trees or under loose soil since both places are safe and hidden from large predators. Their eggs are long and have a small appendage on one side.
It takes about three weeks for the eggs to hatch and the larvae to come out. In this second stage, the larvae are wingless and resemble snakes with legs. They are long and flat with a shiny head and can be about ½ to 1 inch long.
Their head and thorax are rigid, while the abdomen is soft and ready to be fed. They use their sticky legs to scurry around plant leaves or tree bark to find their prey.
They love to feed on larvae or eggs of other insects. The larval stage lasts about one year but may extend to 2-3 years. Snakeflies live almost their entire lives as larvae!
During this time, the terrestrial larvae live in various places – tree bark, wooden floors, rock crevices, etc. They undergo anywhere between 10 to 15 instar stages, feeding and growing continuously.
The prepupal stage lasts for 3 to 5 days only, but larvae don’t cocoon themselves in this period. It’s also believed that snakeflies need to be at a low temperature for some time in order to induce pupation.
Their pupal stage arrives with the spring and lasts about three weeks but might extend up to four to five weeks as well.
Now, the pupa starts to grow tiny wings and becomes closer to an adult snakefly. By the time it’s late summer, the adult stage starts.
The fourth and final stage is the end of the metamorphosis of the snakefly. It is now fully grown and ready to take its first flight and hunt its first aphid.
The overall lifecycle of snakefly might last anywhere between four to five years, but usually, the larva stage is the longest.
What Do They Feed On?
Both adult snake flies and larvae are predators. The adults feed on pollens and insects like aphids, spider mites, caterpillars, etc.
They also feed on honeydew left behind on leaves by aphids and other sugary substances. They also love to ‘clean’ themselves off after eating.
Female snakeflies love to wag their ovipositors as they eat, almost as if they were showing their approval or disapproval of the meal.
What do their larvae feed on?
Snakefly larvae, on the other hand, are completely carnivorous. They often feed on eggs or larvae of other insects.
They may also eat adults of certain arthropods, including springtails, barklice, homopterans, and mites. Snakeflies can also eat dead insects when they are in their larval stage.
What Can You Do If They Are In Your House?
If you find snakeflies in your home, it is possible that they have made their home in your place.
The best thing to do now is to clean your house thoroughly and eliminate all dust particles, even food crumbs, immediately!
Make sure to clean the small gaps in the room and cracks of doors and windows since most snakeflies find their home in these places, or females may lay their eggs there.
Clean the house twice a week, and you will notice that the snakeflies have cleared the area.
However, you should also check your garden for any signs of infestation, and if there are, use a natural pesticide to get rid of it.
Frequently Asked Questions
What is a snakefly larva?
A snakefly larva is a long, snake-like insect with three pairs of sticky legs. Snakeflies often spend one to two years of their lives as larvae.
In their larval stage, they feed on other insects like aphids, caterpillars, and mites. Snakefly larvae can bite humans, but they are neither poisonous nor venomous.
Where do greenhead flies live?
Greenhead flies are recognized easily due to their large and bright green eyes. These flies are usually attracted to calm and moist places.
They are often called the salt marsh horse fly, and you may find them all along the Atlantic coast of North America.
How long do snake flies live?
If they live in the wild, they can easily live up to 2-3 years (on average). Of these, nearly half its life is spent as a larva.
Snakeflies usually raise only one generation in a year. Their larvae overwinter, and the colder temperature helps them pupate and emerge as adults.
How do you fish the snake fly?
Snake flies are a common bait for trout and other fish. You can easily fish them by casting them out and then pulling the line.
This way, there would be no slack when you throw the line into the water. The fly would drag the line down with itself. In fact, there will be much fish willing to come up even as the fly is going down the water.
We hope this article helped you learn something about snakeflies, their larvae, and how they rarely bite humans.
These creatures are harmless, and even though they might look odd to you, they are quite beneficial to your garden.
Thank you for reading!
Watching a snake-like bug in your house flying around is nothing short of a nightmare, and many of our readers have expressed that exact emotion through their emails.
Thankfully, upon learning that the creature is harmless, most readers simply swat them away, or better yet, just let them be.
Letter 1 – Snakefly Larva
Inchworm ant? Location: Davis, California November 17, 2010 8:21 pm Hello, I found this really strange bug in my bathroom last night. It was about an inch long and really aggressive! I tried to catch it in a cup and it started biting it. It ran away from the cup when I tried to sneak up on it and zipped away like an inchworm! I’ve never seen anything like it. It had 6 legs and a really long abdomen… any idea what it could be? Thanks! Signature: confused student Dear confused student, You have had an encounter with the Larva of a Snakefly. These predators, despite their aggressive behavior, are perfectly harmless. Snakeflies belong to the family Raphidiidae and you can compare your image to a photograph we found on BugGuide.
Letter 2 – Snakefly Larva
bug identification request Location: Manteca, California November 28, 2010 4:19 am We’ve found this bug 3 times now – twice on the bed and once in the garage (which is directly below our bedroom). Haven’t been able to find a picture of it anywhere – I hope you can tell us what this thing is! It’s about half an inch long and can move very quickly. The first one my husband saw went in a sandwich bag to try and get identified – I was very surprised that it’s still alive a week later – no food, no air, no water. Thanks for your efforts – looking forward to your answer. Signature: Brenda W. Dear Brenda, The beneficial and harmless Snakefly Larva you have imprisoned in a plastic bag would be much better off if you released it where you found it. According to BugGuide: “Both larvae and adults are predatory, though they are capable of catching and killing only small and weak prey. Snakefly larvae feed on eggs and larvae of various insects, as well as adults of minute arthropods (e.g. mites, springtails, barklice, and homopterans). Adults typically prefer aphids but may eat a wide variety of arthropods. Adults take efforts to clean themselves after feeding. Females have been observed to ‘have a curious habit of frequently wagging their ovipositor during the process of eating, as though expressing satisfaction with the food.’ [pg. 104, Carpenter, 1936]“
Letter 3 – Snakefly Larva
Subject: bug Location: San Francisco bay area October 10, 2012 2:42 am I live in northern California about an hour from San Francisco. I found this bug in on a paper towel in my bathroom sink. It is just the start of Fall here. Can you tell me what it is? It was about a inch long. Almost looks like an earwig with no pinchers. It’s head was very flat looking! Signature: Thank you, Jessica Hunt Hi Jessica, We quickly confirmed that this is a Snakefly Larva by comparing your photo to this image on BugGuide. The information page on BugGuide states: “Both larvae and adults are predatory, though they are capable of catching and killing only small and weak prey. Snakefly larvae feed on eggs and larvae of various insects, as well as adults of minute arthropods (e.g. mites, springtails, barklice, and homopterans). Adults typically prefer aphids but may eat a wide variety of arthropods.”
Letter 4 – Snakefly Larva
Subject: Ant/Caterpillar Crossbreed! Location: Napa, Calfornia December 29, 2016 8:35 pm My wife found this insect on the floor of our kitchen while sweeping. My best guess is that an ant (or termite) and a caterpillar had a forbidden love affair that resulted in this unusual creature. Dark, flat head and thorax, six legs, long mottled abdomen that has small hairs on it, large jaws. When it moves it walks with its legs, and the long abdomen expands and contracts like an caterpillar to keep up, though it moves very rapidly. I’ve lived my whole life in California and never seen an insect like it. In addition, we are in the middle of winter, so a very unusual time to find a new insect. You will impress me indeed if you know what this is. Signature: Jesse Dear Jesse, Based on this BugGuide image, this is a beneficial, predatory, Snakefly larva, and we think the adult Snakefly is much more unusual looking than is the larval form.
Letter 5 – Snakefly Larva
Subject: What’s this bug? Geographic location of the bug: Olympia Washington Date: 09/06/2017 Time: 03:37 PM EDT This is the oddest bug I’ve seen. S/he is roughly an inch and a half long and maybe 4mm wide. I was told it might be a soldier beetle? How you want your letter signed: Tammi Dear Tammi, This is a beneficial, predatory larva of a Snakefly. According to BugGuide: “Both larvae and adults are predatory, though they are capable of catching and killing only small and weak prey. Snakefly larvae feed on eggs and larvae of various insects, as well as adults of minute arthropods (e.g. mites, springtails, barklice, and homopterans). Adults typically prefer aphids but may eat a wide variety of arthropods. Adults take efforts to clean themselves after feeding.”
Letter 6 – Snakefly Larva
Subject — What’s that?? Geographic location of the bug: Northern California Date: 10/25/2017 Time: 11:31 PM EDT Hello bug Man! Can you help me identify what this is? Very thin about an inch to an inch and a half at most. Was in my room… I hope you can shed some light. Many thanks How you want your letter signed: Harsha Dear Harsha, This is a harmless Snakefly larva. According to BugGuide: “Both larvae and adults are predatory, though they are capable of catching and killing only small and weak prey. Snakefly larvae feed on eggs and larvae of various insects, as well as adults of minute arthropods (e.g. mites, springtails, barklice, and homopterans).”