174 



11 (l2). Stripes and spots reddish brown; lighter median indentation in dark 



area of anterior part of frontoclypeus deep; gula light; prosternite 

 in form of a thin, yellowish brown sclerite with dark sclerotized 

 dots laterally 1. L. rhombicus L. (p. 218) 



12 (ll). Stripes and spots darker, blackish brown in some places; median 



indentation in dark area of anterior part of frontoclypeus shallow 

 or indistinct; gula dark; prosternite forming an entire sclerite, 

 yellowish in middle, brown laterally, with black, confluent 

 sclerotized dots; Siberia 3. L. abstrusus McL. (p. 231) 



13 (lO), Groove in anterior third of pronotum with dark stripe in middle; 



case usually covered symmetrically with plant particles or 

 detritus, often trihedral. 



14 (15). Abdominal segment 2 without presegmental lateral gills 



7. L. nigriceps Zett. (p. 234) 



15 (14). Abdominal segment 2 with presegmental lateral gills 



8. L. decipiens Kol. (p. 248) 



16 (1). Head light, with distinct dark, or more or less dark, punctation, 



with indistinct punctation, or uniformly dark, sometimes with 

 only a small, light area in angle of frontoclypeus; anterior third 

 of pronotum light or slightly dark, groove in anterior third, usually 

 with dark stripe in middle; case of varying structure, made of 

 plant or mineral particles. 



17 (20). Head and pronotum mostly light, with large distinct dots. 



18 (19). Median stripe of frontoclypeus and dorsal stripes pale, barely 



visible, or absent; case made of large, longitudinally arranged 



plant fragments 9. L. borealis Zett. (p. 251 ) 



19 (I8). Frontoclypeus mainly light; posterior part with distinct punctation; 



anterior part with dark spots near tentorial pits; dorsal stripes 

 pale, short (beginning from eye), darker anteriorly than posteriorly; 



case smooth, made of sand grains and detritus particles 



10. L. bipunctatus Curt. (p. 255) 



20 (17). Head more or less dark, brown, or darker; punctation sometimes 



indistinct. 



21 (32). Head moderately dark. 



22 (27). Case made of plant fragments. 



23 (2 6). Head brown or reddish brown; groove in anterior third of pronotum 



with dark stripe in middle; case made of plant fragments, straight, 

 narrower posteriorly. 



24 (25). Larva large, 17— 18 mm long; ventral surface with pale, sometimes 



indistinct groups of dots near occipital foramen; case 20—34 mm 



long, built of overlapping, large plant fragments 



17. L. elegans Curt. (p. 278) 



25 (24). Larvae small, 11 — 13 mm long; ventral surface with distinct, dark 



groups of dots near occipital foramen; case 14— 17 mm long, 



smooth, made of small and large plant fragments 



21. L. sericeus Say. (p. 285) 



26 (23), Head and pronotum brownish; groove in anterior third of 



pronotum without dark stripe in middle; case smooth, conical, 

 slightly curved, made of small, transversely arranged plant 

 particles 19. L. sparsus Curt. (p.28l) 



216 



