The adult snakefly has a dark, shiny, flattened head and a prolonged necklike thorax. It can raise its head above the rest of its body, much like a snake preparing to strike. It has long, slender antennae and a brown or dark reddish body that measures 12 to 25 mm (0.5 to 1.0 in) in length. Its four wings are membranous, clear, and heavily veined with a conspicuous spot on the front margins near the tip. When at rest, the wings are held up rooflike over its back. The adult snakefly generally captures only small and weak prey, such as aphids and young caterpillars. The female has an extended, tail-like organ called an ovipositor used to lay clusters of eggs in bark crevices and other hidden areas.
Snakefly eggs hatch into larvae that live under bark and in leaf litter. Larval feeding habits are not well known, but it likely eats various soft-bodied insects such as wood borer larvae and codling moth pupae. The snakefly larva is flattened and long with a shiny, dark brown to black thorax and head with prominent jaws. It resembles the larvae of certain beetles. Its long abdomen has ten segments and is mostly brown to dark red, commonly with pale spots or rings. The larva undergoes a complete metamorphosis without a cocoon stage and develops through 10 or 11 growth stages, or instars.
Scientific classification: Snakeflies are members of the family Raphidiidae, order Neuroptera.