Megaloptera

Definition

An order of holometabolous insects within the superorder Neuropterida, comprising approximately 300 species of alderflies (family Sialidae), dobsonflies, and fishflies (family Corydalidae). Adults are characterized by large, soft bodies, prominent mandibles (especially in male dobsonflies), and similar wing venation to Neuroptera. Larvae are elongate, prognathous, and exclusively aquatic, with filamentous lateral gills on abdominal segments; they are predatory or scavenging, living under stones or in submerged vegetation, and may require several years to mature. Adults are typically short-lived, weak-flying, and often found near water or attracted to lights.

Etymology

From Greek megas (large, great) + pteron (wing), referring to the relatively large wings of adults compared to related groups.

Example

The dobsonfly Corydalus cornutus, with its dramatically elongated male mandibles reaching twice the body length, is among the most visually striking representatives of Megaloptera in North American streams.

Related Terms

• Neuroptera
• Raphidioptera
• Neuropterida
• Sialidae
• Corydalidae
• holometabolous
• aquatic insect
• Prognathous

Usage Notes

Formerly treated as a suborder within Neuroptera, Megaloptera was elevated to ordinal rank based on larval morphology (especially the presence of lateral abdominal gills and distinct pupal cocoon construction) and adult genitalic differences. The order is considered among the most primitive holometabolous lineages. Contrast with Neuroptera (lacewings, antlions), which have terrestrial or fossorial larvae lacking filamentous lateral gills. The name Megaloptera Bethune-Baker, 1908 also exists as a genus of moths (Lepidoptera: Erebidae), a separate and unrelated usage.