Petrophila sp.

[Mark Melton]

This species shows up as larvae and pupae on large cobbles in moderate flows. The adult shows up as a terrestrial moth which lays it's eggs in the water. The larvae and pupae are camouflaged underneath mats on top of and on the sides of cobbles. They're found in the summer months in the Russian River. Mature larvae measure about 9-10 mm and pupae about 9 mm.

Here is an article on fishing them; https://cpw.state.co.us/Documents/LandWater/Riverwatch/EntomologyContents/AquaticMoths.pdf

And another on a wasp that parasitizes them; https://ia800205.us.archive.org/14/items/biostor-76932/biostor-76932.pdf


Larvae with mat


Larvae


Ventral view of larvae


Mat that hides pupae


Immature pupae


Mature pupae