ventral setae of femur almost equally long; dorsal subapical setae of tibia 

 situated near its end, like the dorsal and ventral setae of the tarsus; claw 

 thin, long, but markedly shorter than the very long tarsi and with a strong 

 basal seta. 



A remarkable character of the abdomen are distinct, small, round or 

 oval tergites on segments 3—8; these tergites are situated near the anterior 

 margin of the segment and are not connected with the base of setae; medio- 

 anal and anterior-angle setae of abdomen dark and longer than the others, 

 seta 1 of the 2 ventral setae of the 1st abdominal segment, dark and strong. 

 Claw of anal legs with two dorsal denticles and hooklike spinules above them 

 (Figure 457). 



The case is made of secretion, with thin transparent walls; anterior 

 and posterior ends of case similar, slightly convex (Figure 458). The case 

 has erroneously been described as resembling the cases of Agraylea, but 

 the case of Leiochiton fagesii differs from them in the absence of 

 algae in the walls and in its distinct angles at the anterior and posterior 

 margin. 



Pupa. Length 2.3— 3.0 mm; wing sheaths pointed and long. Anterior 

 angles of case with 2 attachment disks, each with a stalk; posterior angles 

 with one disk. The pupae are found on the lower surface of aquatic plants 

 (Figure 458). 



Mode of life and habitats. Stagnant water and water bodies with 

 a slow current in plant thickets; common in the Volga delta. 



Distribution. European USSR. In addition, Europe. 



5. Genus Orthotrichia Eaton 



Full-grown larva. Length about 3 mm. Slightly flattened dorsoventrally; 

 not laterally compressed. Sutures of head well marked; frontoclypeus 

 large; setae moderately long; seta 9 strong, longer than the others. Labrum 

 asymmetrical, with a beak- shaped median process on the dorsal sclerite. 

 Mandibles flattened; lower blade of left mandible little developed at the base; 

 353 median brush of chetoids situated openly. Sides of meso- and metanotum 

 slightly concave; some setae of pronotum and medioanal setae of meso- and 

 metanotum curved anteriorly. Trochantin free, its hornlike process long. 

 Median sternites absent. The difference in length and form of the forelegs 

 and the other legs is not as great as in Agraylea, HydrOptila and 

 Oxyethira; basal process of femur and distal process of tibia hardly 

 marked also on the forelegs; claws of midlegs and hind legs massive, and 

 long, like the tarsi; ventrodistal chetoid of the tarsi leaf-shaped. First 

 abdominal segment with a narrow, transverse rudimentary tergite; 

 abdominal segment 2 with large lateral processes; sclerite of segment 9 

 oblong, covering the whole segment; anal legs short; claw with 4 setae 

 (2, 3, 7, 8); other setae absent. The case is made of secretion; it is grayish, 

 slightly flattened dorsoventrally; the convex dorsal surface of the case is 

 ribbed, the ventral surface flat. 



Young larva. Head broad, short; thorax and abdomen tapering posteriorly. 

 Midlegs and hind legs not especially long. Setae of thorax and abdomen 



391 



