Biology and morphology of the mature larva of Oxyethira arizona Ross (Trichoptera : Hydroptilidae)

The biology and morphology of the fifth instar of Oxyethira arizona Ross ar e given. Larvae were taken from a cattail stand (Typha sp.) growing in a co nstructed wetland located in southern California. Adults were collected in pan traps placed at the edge and center of the cattail stand. Laboratory ob servations showed that larvae fed on individual cells within filaments of t he green alga Oedogonium which grew epiphytically on submerged portions of the plants. Larvae used asymmetric mandibles for simultaneously grasping an d piercing the cell walls to remove the liquid contents. Most (88.1%) of th e adults taken were males, and 82.1% of males and all females were obtained at the periphery of the cattail stand. This is the first report of a hydro ptilid larva feeding on Oedogonium, and is the first time O. arizona has be en reported from California.