LIBRARY

TRICHOPTERA 417
swift streams. The North American species, Psilotreta frontalis Banks of the
eastern states, lives on the riffles and constructs a slightly curved cylindrical
case covered with sand. Prior to pupation the larvre congregate in considerable
numbers, attach the cases parallel, and close each end with a small pebble
FIG. 147. Caddisflies. A, larva removed from case and B. adult female of RhYacophila
fenestra Ross, a common species frequenting the rocky streams of southern Illinois; C, adult
DoloPhilus shawnee Ross also from Illinois. (After Ross, 1938.)
(Lloyd 1921). Important genera are: Psilotreta Banks (Holarctic), Marilia
F. Muller (American), Odontocerum Leach (Palrearctic), and Nerophilus Banks
(North American).
Family SERICOSTOMATIDlE McLachlan 1876 (Ser'i-co-sto-mat'i-dc.e, from
the Greek O''1'JPtKbs, si1ken, + (J'Tb/Jo" mouth).
A large and widely distributed family of caddisfiies, the antennre of whicli
are broadly developed at the base with a large hairy scape often longer than
the head. The eruciform Iarvre live mostly in running fresh water and to a
lesser degree in ponds and lakes while one species; listed below, is marine.
Tracheal gills are present only in the subfamilies LEPIDOSTOMATlNJE and