432 antez-ior margin. Mandibles narrow, straight or curved, serrated in the 

 middle. Wing sheaths usually pointed, rarely blunt. Midlegs natatorial. 



Posterior angles of abdominal segment 1 with spinulose tubercles. Plates 

 of holding apparatus presegmental on segments 3 — 6 or 3 — 7, postsegmental 

 on segment 5. Gills as in the larva, with a single or several filaments. 

 Lateral line with short grayish setae on segments 3—8. Anal appendages 

 rodlike, usually narrow, long, rarely short. 



Case shorter than in the larva but similar in form and material; anterior 

 and posterior membranes with slitlike or round opening. 



Mode of life and habitats. In various types of running water, 

 from highland brooks to large rivers in the plains, with slow or rapid current; 

 small and large bodies of stagnant water, different types of lakes, ponds, 

 floodplain water bodies, and small, seasonal water bodies. 



Distribution. Throughout the USSR. Cosmopolitan. 



Key to Genera 

 Full-grown larva 



1 (4). Gills with several filaraents; body and case narrower posteriorly; 



case made of sand grains or of secretion, in form of a short cone 

 in some species, wide anteriorly, convex dorsally, flat ventrally. 



2 (3). Head with contrasting variegated pattern, or uniformly pale with 



barely distinguishable pattern 1. Athripsodes Billb. (p. 542) 



3 (2). Head brownish dorsally, without pattern . . 2. Homilia McL. (p. 578) 



4 (1). Gills single. 



5 (14). Mandibles with 2 blades; gula square or of different form. 



6 (11). Hind tibia divided, hind tarsus sometimes divided; case made of 



detritus, sand grains, secretion, or fresh fragments of plants. 



7 (8). Hind tarsus divided; case straight, made of detritus or detritus and 



sand grains 3. Mystacides Berth, (p. 579) 



8 (7). Hind tarsus not divided; case made of small, green, plant fragments, 



long, of regular form, 



9 (10). Hind legs natatorial; case in form of a narrow cone, sometimes very 



long, covering fragments arranged in a spiral 



4, Triaenodes McL. (p. 500 ) 



10 (9). Hind legs not natatorial; covering fragments similar but arranged 



differently 5. Erotesis McL. (p. 61 1) 



11 (6), Hind tibia not divided; case made of secretion or sand grains. 



12 (13). Hind legs natatorial; case straight, conical, made of secretion, . . 



6. Leptocerus Leach (p. 613) 



13 (12). Hind legs not natatorial; case curved, made of sand grains 



7. Adicella McL. (p. 622) 



14 (5). Mandibles with a single blade; gula small, poorly differentiated . . 



8. Oecetis McL. (p. 624) 



54! 



