Most are nocturnal. Alderflies Alderfly larvae have thick brown skin, grow to about an inch long, have a single pointy tail, and tend to hide out. The male is on the left. The photo is courtesy of Kevin in Kentucky. The adults grow up to 2.7 inches, and the male has inch long curved mandibles.
Adult males have jaws half the length of their body.
Females' jaws are smaller but can bite. Hellgrammites live for up to 2 or 3 years in the water while the adults live only a few days. Hellgrammites are often used for bait. The larvae use their killer jaws to capture and eat insects and small animals. The Eastern Dobsonfly is Corydalus cornutus .