in the larva. Holding apparatus segments 3—6 or 3—7; postsegmental 

 plates with a few hooks. Anal rods slightly narrower distally, ends curved 

 laterally. 



Mode of life and habitats. Detritophagous and phytophagous, 

 some species feed on animals if plants are not available. Stagnant water; 

 some species in running water. 



Distribution. Throughout the USSR. In addition, Europe, Iran, 

 Pakistan, Mongolia, China, Japan, North America. 



Key to Species 

 Full-grown larva 



1 (16). Coloration of head and pronotum distinct, consisting of stripes 



and dots; frontoclypeus more or less broadly dark in anterior part, 

 other surface with wide, dark, longitudinal stripe forming a 

 T-shaped figure together with anterior stripe; anterior third of 

 pronotum dark; case made of fine or coarse detritus, fragments of 

 plants, mollusk shells; sand grains sometimes present among 

 other material. 



2 (9). Dark transverse stripe in anterior part of frontoclypeus, wide, 



almost reaching or reaching frontal sutures; indentation shallow, 

 brownish or yellowish, sometimes with indistinct outline, in 

 . „„ middle of anterior margin. 



3 (8). Ventral surface of head, including gula, grayish brown; groove 



in anterior part of pronotum with or without dark stripe in middle; 

 case bulky, with rough surface, made of large pieces of detritus, 

 arranged obliquely and transversely, or more or less smooth, 

 with fine pieces of detritus, small fragments of stalks, or mollusk 

 shells. 



4 (7). Anterior third of pronotumblackishbrown; groove without dark 



stripe in middle. 



5 (6). Gills usually present on segment 8 . . . . 2. L. politus McL. (p. 227) 



6 (5). Segment 8 usually without gills. . . 4. L. marmoratus Curt. (p. 233) 



7 (4). Anterior third of pronotum brown; gro.ove with dark stripe in 



middle 5. L. flavlcornis Fabr. (p. 236) 



8 (3). Ventral surface slightly dark in some places; gula usually light; 



groove in anterior third with dark stripe in middle; case inade of 

 plant particles, arranged regularly and transversely so that middle 

 of case is usually wider than ends, and case is barrel-shaped; case 

 sometimes made of fragments of moss, wide, almost spherical. . . 

 . 6. L. stigma Curt. (p. 240) 



9 (2). Dark transverse stripe in anterior part of frontoclypeus less 



wide, not reaching frontal sutures; light median indentation near 

 anterior margin of stripe sometimes deep, dividing dark area 

 into 2 parts. 

 10 (13). Groove in anterior third of pronotum without dark stripe in middle; 

 case made of coarse particles of tree detritus, sometimes bulky, 

 or of small pieces of detritus, rarely with sand grains among 

 detritus. 



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