Femur strongly deformed, flattened dorsoventrally, very convex dorsally 

 (especially in the basal part); ventral surface flattened, slightly concave 

 and sclerotized near the anterior margin; membranous part small, present 

 only near the base; margin of femur projecting anteriorly in form of a 

 crest at the boundary with the ventral surface; it projects like a beak 

 distally; two ventral setae situated close together further basally; one 

 spinelike and short, the second longer and light; posterior seta short and 

 situated subventrally; basodorsal seta small, situated in the middle of the 

 segment; distodorsal seta short; an additional small seta near the base. 



296 Tibia short, with a deep, basoventral notch, with a distal beak- shaped 

 process like the femur; all 6 setae present; one of the distoventral setae 

 light and longer than the others. 



Tarsus also short and with a distal beak-shaped process; short dorsal 

 setae widely separated, one ventral seta light and long. 



Claw (Figures 341 and 342) extremely long, thin like a seta, blunt and 

 slightly club-shaped at the end; basal seta in form of a short, strong, blunt 

 spine (Figure 342, B). 



Midlegs and hind legs thin, normal; some setae very long (Figure 335). 

 Coxa (Figures 339 and 340) with a small distodorsal notch; all 3 dorsal 

 setae black and long; basal seta situated near the base of the segment; the 

 anterior and posterior apical setae situated at the sides of the notch; 

 anterior surface setae situated one behind the other and large; distoventral 

 setae small and thin, situated close together; posterior seta shorter than 

 anterior seta. 



297 Trochanter membranous dorsally; its dorsal angles clearly marked; 

 subapical posteroventral seta long. 



Femur not longer than coxa; anterior seta situated subapically and 

 longer than the others; basoventral seta short; there is a longitudinal row of 

 minute spinules further distally; both dorsal setae short. 



Tibiae and tarsi straight, rodlike and narrow; setae near the distal 

 margin small. Dorsal setae of tibia straight, thin, situated at the apex and 

 subapically; ventral setae small and strong. Tarsus shorter and thinner 

 than tibia; both dorsal setae situated subapically. Claw of normal form, 

 thin, slightly curved, with a small basal seta. 



Abdominal segments 1 — 7* of the same form: segment 1 shorter but not 

 narrower than the following segments; anterior -margin setae small; 

 anterior -angle setae (except the first segment) dark and very long, longer 

 than the thoracic setae; they stand close to the anal seta on segments 6—7; 

 medioanal seta as long as the anterior-angle seta; a small intermediate seta 

 and a lateral seta on the outer side near the base. Pleural setae 2 in 

 number and situated on a small light spot; one of them long, the second 

 small and thin. Intermediate ventral seta small, distinct, situated on a 

 yellow sclerotized dot near the anterior margin of the sclerite. 



Pupal cocoon (Figure 335) straight, almost cylindrical in the middle; 

 ends of the cocoon fastened to the wall of the thick pupal chamberlike case 

 by strong strands; pupal chamber covered with coarse sand grains. 



Mode of life andhabitats. Brooks with cool water. 



Distribution. USSR: Maritime Territory. 



We could not examine segments 8 and 9 at the end of the body of the prepupa in our material; we mention 

 only some setae of the eighth segment. 



321 



