Raphidioptera

Definition

An order of predatory holometabolous insects, commonly called snakeflies, characterized by an elongated, neck-like prothorax that gives the adult a distinctive serpentine appearance. The order comprises two extant families (Raphidiidae and Inocelliidae) with approximately 260 species worldwide. Raphidioptera represents one of the most basal lineages within Neuropterida and was historically classified within Neuroptera. Adults and larvae are both predatory, with larvae inhabiting bark crevices and taking up to two years to develop through multiple instars. The group is primarily temperate in distribution and notably absent from tropical regions and the Southern Hemisphere.

Etymology

From Greek rhaphís (needle) + pterón (wing), referring to the slender, needle-like appearance of the wings and body

Example

The snakefly Agulla adnixa (family Raphidiidae) is a common species in western North America, where both adults and larvae prey on small arthropods in coniferous forest habitats.

Synonyms

• snakefly
• Snakeflies

Related Terms

• Neuropterida
• Neuroptera
• Megaloptera
• holometabolous
• prothorax
• Raphidiidae
• Inocelliidae

Usage Notes

Raphidioptera is treated as a distinct order separate from Neuroptera in modern classifications, though older literature may refer to snakeflies as neuropterans. The elongated prothorax is diagnostic and distinguishes adults from superficially similar alderflies and lacewings. The order's relict distribution and absence from the tropics reflect its ancient evolutionary history and Cretaceous-era decline.