Dorsal process of abdominal segment 1 wide, large; lateral processes 

 displaced ventrally and supported laterally by a narrow black strip-like 

 sclerite; apex of process with light spinules near distal margin. Gills with 

 several filaments, or only one. 



The genus may be divided into 3 groups of species according to morphology 

 of the larvae: 



1. Head oblong, without light stripes; gula triangular; mesonotum 

 distinct, with straight, oblique streaks in the posterior angle, case made of sand 

 grains, with round cross section (Athripsodes aterrimus, A. 

 cinereus, A. bilineatus). 



2. Head wide, with distinct, light stripes, gula trapezoidal or cup-shaped; 

 mesonotum thin, indistinct, sometimes transparent, with large, distinct, 

 bracketlike, black or brownish streaks in posterior angle; case made of 

 sand grains, flattened dorsoventrally (A . excisus, A. annulicornis). 



3. Larva as in group 2; case made of secretion, flattened dorsoventrally 

 (A. fulvus, A. senilis). 



The first species in each group is of variegated color with distinct 

 pattern of dots on head and pronotum; the others are pale. 



Sclerite of abdominal segment 9 distinct, brownish, or absent. Claw of 

 anal legs small, v/ith a large dorsal denticle or with 2 denticles. 



Case conical, curved, made of sand grains or secretion, flattened 

 dorsoventrally in some species. 



Pupa. Length 6— 12 mm. Labrum with small, pointed median process. 

 Mandibles wide, curved apically. Wing sheaths narrow, reaching abdominal 

 segments 6—8. Gills as in larva, often less numerous. Dorsal side of 

 abdominal segment 1 with a process with spinules directed posteriorly, a 

 sclerite with spinules directed anteriorly in middle. Presegmental plates 

 of holding apparatus on segments 3—7 or 3— 8, postsegmental plates on 

 segment 5. Anal rods long, pointed, rarely short, wide, with 4 setae, last 2 

 setae small, situated distally. 

 43 4 Case made before pupation attached at both ends by ligaments or adhesive 

 disks; membrane with round or slitlike opening. 



Mode of life and habitats. Brooks and rivers, including large 

 rivers in plains, with running water; large and small lakes, large clear 

 ponds, lakes of river floodplains. 



Distribution. Throughout the USSR. Cosmopolitan. 



Key to Species 

 Full-grown larva 



1 (6). Head slightly oblong, without light stripes lateral to frontal suture; 



gula narrow, triangular; mesonotum present, with short, coarse, 

 black or dark brown, oblique streaks at posterior angles; case 

 made of sand grains. 



2 (3). Head and thoracic tergites with distinct pattern of dark stripes and 



large dots 1. A. aterrimus Steph. (p. 545) 



3 (2). Head with pale, indistinct pattern. 



4 (5). Ventral side of head broadly black; tergites of mesothorax with 



more or less distinct dots 2. A. cinereus Curt. (p. 554) 



543 



