Explanation of Names
PHILOPOTAMIDAE: from the Greek "philos" (loving) + "potamos" (river); larvae live in fast-flowing portions of rivers and streams
FINGERNET: larvae construct groups of silken nets shaped like fingers
Numbers
47 species in 3 genera in North America (
nearctica.com)
Identification
Adult: many species are uniformly dark brown to black; 5th segment of maxillary palp is 2-3 times longer than the 4th segment; females of the eastern species Dolophilodes distinctus are wingless
Larva: have a membranous metanotum and T-shaped membranous labrum
[How to Know the Insects. Roger Bland. 1978]
Range
throughout North America and much of the world
Habitat
larvae in fast-flowing portions of rivers and streams; adults on nearby vegetation, and are attracted to artificial light
Season
both sexes of Dolophilodes distinctus are active year-round; others from spring through fall
Food
larvae are filter-feeders, eating small particles of plant and animal matter plus algae such as diatoms that become trapped in the meshes of their nets
Remarks
Larvae spin very fine-meshed nets, usually grouped together on the undersides of rocks near the upstream edge. The nets collapse when the rocks they are attached to are removed from the water.
Internet References
larva images of
Chimarra species, plus description and biology (Wilfred Laurier U., Ontario)
systematics and distribution (Roger Blahnik, U. of Minnesota)
