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*** Note: KnowYourInsects.org does its best to include correct identifications of insect photos. It’s always possible that we made a mistake, however, so if you see a misidentification, please contact us and we will correct it. Thanks!

Order Megaloptera: the dobsonflies, alderflies and fishflies — Examples
Families represented below:
Corydalidae (the dobsonflies and fishflies)
Sialidae (the alderflies)

Corydalidae (the dobsonflies and fishflies)

Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ The size of the jaws and antennae vary between the male and female eastern dobsonfly. The female (shown here) has smaller jaws and thinner antennae.
Photographed by: Margaret Ritchie. Identified by: KnowYourInsects.org. Location: Burlington, Michigan, USA. Date: 13 July, 2016.
Margaret says, “About 3" long - never seen anything like this before!” She adds, “I dont get skittish around bugs or creepy-crawlies but I admit this one got me a bit uncomfortable :-) ”
Eastern Dobsonfly, male, Corydalus cornutus
Eastern dobsonfly, male, Corydalus cornutus, family Corydalidae.
□ The jaws on this male eastern dobsonfly are huge! Despite their scary appearance, the male cannot use those jaws to bite. The female, on the other hand, can bite hard enough to draw blood from a person’s finger.
Photographed by: Charine Dowdell. Identified by: KnowYourInsects.org. Location: Carrollton, Georgia, USA. Date: 25 July, 2017.
Charine says, “Saw this at a gas station.... I love insects and am extremely fascinated.”
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ Be sure to read the photographer’s comments below about her encounter with this eastern dobsonfly — great story!
Photographed by Ginger Bennett and identified by her son (great job!). Location: Wakefield, Louisiana (at the Mississippi state line), USA. Date: 10 August, 2016.
Ginger says, “This mysterious creature landed on my arm while filling up with gas. I screamed and tried to shake off the nearly 4-inch-long bug, but it would not budge. I grabbed a bottle of water and poured it on my arm and the creature flew into my front passenger seat. This is where I took a picture. My 8-year-old son researched it online and via Google we found your site and identified this as an Eastern Dobsonfly. Thank you for the fascinating information!”
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ These photos show the top and bottom view on an adult eastern dobsonfly. The young, called hellgrammites, live underwater in streams and rivers. Hellgrammites are excellent predators of other invertebrates. If they are handled, hellgrammites will defend themselves by giving a surprisingly strong pinch.
□ Adult female Eastern Dobsonflies (like this one) only live a week or so, and the males only survive for about three days. Eastern Dobsonfly larvae, on the other hand, can live up to three years.
Photographed by: Timothy Fiala. Identified by: KnowYourInsects.org. Location: Southwest Iowa, USA. Date: 14 July, 2016.
Eastern Dobsonfly, male, Corydalus cornutus
Eastern dobsonfly, male, Corydalus cornutus, family Corydalidae.
□ Seeing an adult male eastern dobsonfly is a bit of an unusual event, because they only live for about 3 days. The females live for a bit longer: up to 10 days. Like many insects, the longest part of their lives is spent as larvae. Dobsonfly larvae, known as hellgrammites, survive for years in the water before becoming adults.
Photographed by: Karen Warner. Identified by: KnowYourInsects.org. Location: Lebanon, Pennsylvania, USA. Date: 25 July, 2020.
Eastern Dobsonfly, male, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ With the huge pair of jaws on this male eastern dobsonfly, many people might not even notice the even-longer antennae extending to the sides or the beautiful veining on the wings.
Photographed by: the Wallace family. Identified by: KnowYourInsects.org. Location: along the Appalachian Trail, Maryland, USA. Date: 15 June, 2020.
The Wallace family estimated it was 4-5 inches (10-13 cm) long.
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
Eastern dobsonflies differ from fishflies (seen elsewhere on this page) by their larger overall size, more robust jaws and head shape, which widens abruptly above the neck-like thorax (the fishfly’s head flares out much more gradually).
Photographed and identified by: Bill Dreschel. Location: State College, Pennsylvania, USA. Date: 7 July, 2020.
Bill says this individual was 2.5 to 3 inches long, and adds, “Impressive mandibles!”
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ The female eastern dobsonfly lays hundreds of eggs at once, usually on a leaf or twig that overhangs a stream. When the eggs hatch in a week or two, the young (called hellgrammites) drop into the water, where they drift off to a suitable, sheltered, place to live, which is usually beneath an underwater rock or log.
Photographed and identified by: Bernie Tomsa. Location: West Bloomfield, Michigan, USA. Date: 29 May, 2020.
Bernie was fortunate to find both adult Eastern Dobsonflies and Spring Fishflies in his yard. His photos of the Spring Fishfly are posted elsewhere on this page.
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ This photo of an eastern dobsonfly shows the pretty pattern on the top of its head, as well as the light-colored spots on its wings.
Photographed by: Paul Walker. Identified by: KnowYourInsects.org. Location: Midland, Michigan, USA. Date: 5 July, 2019.
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ Although eastern dobsonflies have such large wings, they are rather weak fliers and flutter more like butterflies or moths. In fact, many people mistake them for moths.
Photographed by: Jason Cavalier. Identified by: KnowYourInsects.org. Location: Waxhaw, North Carolina, USA. Date: 5 July, 2020.
Jason shooed this one into a large cage. He says, “I’ll turn him loose tonight after showing to some kids.” KnowYourInsects.org bets those kids loved seeing this beastie!
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ The eastern dobsonfly has a species name of cornutus, which is a Latin word for horns, a reference not to horns, but to the long and rather horn-like jaws of the male eastern dobsonfly shown elsewhere on this page. The female, pictured here, has smaller jaws than the male, but hers are actually much more powerful.
Photographed by: Steven Carlyle. Identified by: KnowYourInsects.org. Location: Xenia, Illinois, USA. Date: 25 June, 2020.
Eastern Dobsonfly, female, Corydalus cornutus
Eastern dobsonfly, female, Corydalus cornutus, family Corydalidae.
□ This photo of an eastern dobsonfly shows the pretty pattern on the top of its head, as well as the light-colored spots on its wings.
Photographed and identified by: Vickie Stewart. Location: near the Great Smoky Mountain Park, Tennessee, USA. Date: 11 July, 2020.
“I found this on the stone siding. We have a creek maybe 50 feet away.”
Hellgrammite, larva of an Eastern Dobsonfly, Corydalus cornutus
Eastern dobsonfly, larva (called a hellgrammite), Corydalus cornutus, family Corydalidae.
□ This pair of photographs shows the top and bottom views of a hellgrammite, which is the larva of an eastern dobsonfly. Hellgrammites, which live beneath submerged logs and rocks, can grow to 2-3 inches (5-7.5 cm) long. They have powerful jaws and will give a hard bite to defend themselves. Hellgrammites sometimes temporarily crawl onshore during hard rains. When they are ready to pupate, they come onshore, often in mud under a log, and finally emerge as an adult.
Photographed by: Deanne Vance. Identified by: KnowYourInsects.org. Location: middle Tennessee, USA. Date: 13 May, 2019.
Deanne says, “I found this under my bed, already dead. It’s about an inch and a half long with six long jointed legs, and has what looks like pinchers on its face.”
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Spring Fishfly, Chauliodes rastricornis
Spring fishfly, female, Chauliodes rastricornis, family Corydalidae.
□ The female spring fishfly has much thinner antennae than the male, pictured in the next photo.
Photographed and identified to order by: Chasity Phelps. Identified to species by: KnowYourInsects.org. Location: Auburn, Kentucky, USA. Date: 13 June, 2018.
Spring Fishfly, Chauliodes rastricornis
Spring fishfly, male, Chauliodes rastricornis, family Corydalidae.
□ This is a male spring fishfly. Males have antennae with long, comb-like teeth (shown here), while the females’ antennae have much shorter teeth that look more like the teeth on a saw. Comblike antennae are known by the term pectinate antennae, saw-like antennae are called serrate.
Photographed by Jackson Bennett. Identified by: KnowYourInsects.org. Location: Whitestown, Indiana, USA. Date: 30 June, 2016.
Jackson says, “It was really windy the other day and I think that may have been the reason he died.”
Spring Fishfly, Chauliodes rastricornis
Spring Fishfly, male, Chauliodes rastricornis, family Corydalidae.
□ Notice that the wings in this spring fishfly are about twice as long as the body. The name of the order, Megaloptera, fits — it literally means “large wings” in Greek.
Photographed by Jackson Bennett. Identified by: KnowYourInsects.org. Location: Whitestown, Indiana, USA. Date: 30 June, 2016.
Spring Fishfly, Chauliodes rastricornis
Spring fishfly, male, Chauliodes rastricornis, family Corydalidae.
□ Two similar fishflies are the spring fishfly and the summer fishfly. The spring fishfly (shown here) has a mostly light-colored head with dark markings, while the summer fishfly has a mainly dark head with light markings.
Photographed by Wendy Hoeksema. Identified by: KnowYourInsects.org. Location: Williamsburg, Michigan, USA. Date: 15 July, 2018.
Wendy says, “It was hanging out on the siding of house near porch light.” She adds that she a pond is also nearby.
Spring Fishfly, Chauliodes rastricornis
Spring fishfly, female, Chauliodes rastricornis, family Corydalidae.
□ This female spring fishfly has pectinate antennae that look like a one-sided comb with very short teeth. The male has the same setup, except the teeth of the comb are much longer.
Photographed by: Stacey Jones-Garrison. Identified by: KnowYourInsects.org. Location: mid-Michigan, USA. Date: 28 May, 2020.
Stacey says, “I do indeed feel fortunate to have witnessed a fishfly during its brief land visit!”
Spring Fishfly, Chauliodes rastricornis
Spring fishfly, male, Chauliodes rastricornis, family Corydalidae.
Spring fishflies live most of their lives (several years!) as underwater larvae, and then crawl onto shore — often many at the same time — to transform into adults. The adults only survive for about a week, but they pack a lot into that week: they mate and lay eggs in that short time.
Photographed by: Bernie Tomsa. Identified by: KnowYourInsects.org. Location: West Bloomfield, Michigan, USA. Date: 29 May, 2020.
Spring Fishfly, Chauliodes rastricornis
Spring fishfly, female, Chauliodes rastricornis, family Corydalidae.
□ The spring fishfly’s species name of rastricornis is borrowed from the Latin words rastrum and cornu, which mean rake and horn, respectively. This is in reference to the rake-like “horns” or antennae in this species.
Photographed and identified by: Andrea Wolfe. Location: Sullivan (near Muskegon), Michigan, USA. Date: 11 June, 2018.
Andrea says, “This insect was on our grill cover last night. It was like nothing I had seen before, and the second insect I had encountered in the same day that I had never seen before! I decided to take an image and try to find out what this was. Sad to see its lifespan is so short; would be a great bug to catch and show my kids, but would not want to waste what precious time it has to live.”
Fishfly, Corydalidae
Fishfly, male, subfamily Chauliodinae, family Corydalidae.
Fishflies can be distinguished from dobsonflies (pictured elsewhere on this page) by their antennae. Fishflies have combed or pectinate antennae that look like a one-sided comb (as seen here), while dobsonfly antennae look more like thin threads or strings of tiny beads. Photographed and identified by: Phyllis Delesandro. Location: Jackson, New Jersey, USA. Date: 28 July, 2018.
Phyllis says, “I love taking pics with my microscope and my iphone.” KnowYourInsects.org appreciates the photos!
Summer Fishfly, Chauliodes pectinicornis
Summer fishfly, Chauliodes pectinicornis, subfamily Chauliodinae, family Corydalidae.
□ This photo of a summer fishfly shows the hind wings with their long parallel veins. See the photographer’s great description of this insect below.
Photographed by: Liz MacKay. Location: Nova Scotia, Canada. Date: 5 August, 2019.
Liz says, “I found this bug while I was working back shift, saved it from a spiderweb. It’s like a weird hybrid of a dragonfly and a moth, but with an ant-like face. Very cool find.”
Summer Fishfly, Chauliodes pectinicornis
Summer fishfly, female, Chauliodes pectinicornis, subfamily Chauliodinae, family Corydalidae.
□ This closeup of a female summer fishfly”s head shows small lumps between the two large compound eyes and behind the antennae. They are ocelli, or simple eyes. Note also the pectinate (comb-like) antennae: Compared to the male, the female has much shorter “teeth” on the comb. The photographer estimated it at 6.6 cm (2.5 inches) long.
Photographed by: Joe Geller. Identified by: KnowYourInsects.org. Location: Upstate New York, USA. Date: 23 June, 2020.
Joe says, “It was definitely alive and was watching me, even moving a bit, but otherwise somewhat dormant (near 90 degrees, in the shade).”
Summer Fishfly, Chauliodes pectinicornis
Summer fishfly, Chauliodes pectinicornis, subfamily Chauliodinae, family Corydalidae.
□ The leading edge of the wings on this summer fishfly shows the distinctive row of windowpane-like veining in this family of insects. The two side photos depict the typical head-bowed posture. See the photographer’s comment below.
Photographed by: Elmer LeSuer. Location: Kingston, New York, USA. Date: 24 July, 2019.
Elmer found this one on the wood siding of his house. He says, “The siding was painted recently (last summer), so I can only assume it was eating pollen or algae.” KnowYourInsects.org says, “Fishflies do indeed eat algae, as well as insects, such as immature dragonflies and water beetles, that they grab from the water, and also earthworms and other small creatures they find on land.
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Dark Fishfly, Nigronia serricornis
Dark fishfly, Nigronia serricornis, subfamily Chauliodinae, family Corydalidae.
□ The white markings on this dark fishfly look almost like staining or debris, but they are part of the insect. Some of the white markings on the hind wing are also visible in this photo. This species is about 1.5 inches long (3.8 cm).
Photographed by and identified as a fishfly by: Tony Ertola. Identified to species by: KnowYourInsects.org. Location: Carmans River, Yaphank, New York, USA. Date: around 2018.
An avid fly angler, Tony says he enjoys the entomology part of trout fishing, adding, “So many cool creatures live in the rivers!” He spotted this Dark Fishfly at night.
Dark Fishfly, Nigronia fasciata
Dark fishfly, Nigronia fasciata, subfamily Chauliodinae, family Corydalidae.
Dark fishflies in the genus Nigronia look quite similar. This species, Nigronia fasciata, has more white on its forewings (as seen in the photo at right) than Nigronia serricornis (previous photo), so even though this is only a partial insect (the head is missing), it is possible to identify it.
Photographed by and identified as a fishfly by: Tony Ertola. Identified to species by: KnowYourInsects.org. Location: East Branch of the Delaware River, New York, USA. Date: 16 June, 2020.
Tony says, “It must have just been decapitated as it was still moving its abdomen when I picked it up.”

Sialidae (the alderflies)

Alderfly
Alderfly, genus Sialis, family Sialidae.
Photographed by Ed Whitney. Identified by: KnowYourInsects.org. Ed says, “We’ve have these at our cottage for many years. They have odd eggs that are laid on our boat cover and dock posts. They just look like dirt.” Location: Presque Isle, Michigan, USA. Date: 30 June, 2016.
Alderfly
Alderfly (genus Sialis), family Sialidae.
□A closer look at an alderfly.
Photographed by Ed Whitney. Identified by: KnowYourInsects.org. Location: Presque Isle, Michigan, USA. Date: 30 June, 2016.
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Photos at the top of this website are (from left to right): potato beetle (Leptinotarsa decemlineata) — photo credit: Scott Bauer, U.S. Department of Agriculture; ebony jewelwing (Calopteryx maculata)— photo credit: U.S. Fish and Wildlife Service; sweat bee (Agapostemon splendens) — photo credit: Natalie Allen and Stephanie Kolski, U.S. Geological Survey; preying mantis, monarch butterfly (Danaus plexippus), hellgrammite (aka toe biter) larva and eyed click beetle (Alaus oculatus) — photo credit: Leslie Mertz; Halloween pennant (Celithemis eponina) — photo credit: Kay Meng, U.S. Fish and Wildlife Service.

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