SNAKEFLIES (RAPHIDIOPTERA) OF BRITISH COLUMBIA

Raphidiidae, Agulla sp., photo by M.B. Cooke & R.A. Cannings

by

R. A. Cannings and G. G. E. Scudder 

Copyright © 2007 - All rights reserved

Introduction

Small to medium sized, elongate and fragile insects. Head prognathous with large eyes and biting, mandibulate mouthparts. The antennae are long, slender and filiform, and the head may or may not possess ocelli. The prothorax is very characteristic, being slender, cylindrical and neck-like, being as long as or longer than the length of the pterothorax. This gives these insects a rather snake-like appearance, hence the common name.

The forewings and hindwings are similar, lack an extensive anal fan, and are held roof-like over the abdomen when at rest. The forewings possess a distinct pterostigma. The legs are not specialized, and have a 5-segmented tarsus. Cerci are absent, and females possess a long, slender, exserted ovipositor.

Adults can be found in early spring, and fly only a short distance. They feed actively on small bodied insects, including their own congeners if put together. They are also reported to take nectar.

Abdominal vibration is usually a component of the courtship behaviour. Females use the ovipositor to deposit eggs singly or in small batches in bark, crevices, in debris or under the body of mature scale insects. The elongate larvae are terrestrial, with mandibulate, chewing mouthparts. They live in bark crevices, or in areas with dead leaves or debris. They are aggressive predators, feeding on small arthropods. Pupation takes place in dead leaves, debris or crevices. There is no cocoon. And the pupa is free-living, active and able to use it’s mandibles.

The group is primarily Holarctic, and in North America is confined to the west of the eastern slopes of the Rocky Mountains.

Worldwide there are two extant families.