Family Corydalidae: Dobsonflies And Fishflies

Adults: Corydalid adults are large insects (40-75 mm), often with mottled smoky white wings. The wings of some species are dark with light patterns. The males of some species have extremely long mandibles.

Larvae: Corydalidae larvae are the largest of all aquatic insects. They have eight pairs of abdominal filaments and two anal prolegs. Dobsonflies (hellgrammites) have filamentous gill tufts at the base of each lateral filament. Fishflies have tubular spiracles or respiratory tubes extending from the base of abdominal segment eight.

Habitat: The larvae occupy nearly all permanent aquatic environments but may burrow in mud if the water dries up. Most species are nocturnal as adults and can fly great distances. They are commonly found around lights at night. Diurnal (daytime) species are normally seen near their hatch site.

Ecology: Common names like ?toebitter? and ?hellgrammite? are true to form as corydalid larvae are large, active and do not like to be disturbed. They will consume any animal they can grab and swallow. The larvae breath through lateral gill filaments coupled with either tufts of gills or respiration tubes. While the large winged adults may look vicious, they do not feed. Only liquid is consumed as their guts do not function. Adults are short lived so they must locate a mate quickly. Scents are used by mating corydalids to assist in finding a mate. Adults breath via thoratic spiracles.

Reproduction: A holometabolus (complete) life cycle that takes 2-5 years to complete. Adults emerge from late spring through mid-summer. Eggs are deposited in rows on the underside of leaves hanging over water. Adults live up to two days. The first instar larvae falls out of the egg case into the water or dry streambed. They quickly burrow in the substrate where they grow into voracious eaters.