Case made of sand grains, smooth, conical, slightly curved. 

 Mode of life and habitats. Clear brooks and rivulets. 

 Distribution. The European USSR, Siberia, Far East. In addition, 

 Europe, North America. 



Key to Species 

 Full-grown larva 



1 (2). Fi'ontoclypeus not of uniform color, darker anteriorly; wedge- 



shaped pattern of posterior part consisting of dark dots. Each 

 half of mesonotum divided into 2 sclerites. Western and north- 



wester-n parts of the European USSR 



2. M. setiferum Pict. (p. 498) 



2 (1). Frontoclypeus of uniform color, mat brown, wedge-shaped pattern 



replaced by indistinct light dots. Each half of mesonotum entire. 

 The Caucasus 1. Micrasema sp. (p. 493) 



1. Micrasema sp., larva nova='' 



Full-grown larva. Length 3—4 mm. Head (Figure 650, A) slightly 

 oblong, almost round dorsally, brown; frontoclypeus wider in area of 

 anterior frontal seta than at anterior margin; frontal sutures curved inward 

 anteriorly; dorsal ridge more distinct anteriorly; frontoclypeus with 

 numerous flat, dark brown tubercles covering most of anterior part and 

 middle between tentorial pits; similar tubercles lateral to epicranial suture 

 in anterior part and near fork of frontal sutures; posterior part of fronto- 

 clypeus with sever-al large dots; pei-iocular area large, whitish; ventral 

 surface mainly brown, scaly, rough, smooth near occipital foramen, pale 

 yellowish, with lai-ge light dots. Gula large, nearly square, chestnut brown, 

 lighter and narrower antei'iorly; surface of gula slightly rugose 

 (Figure 650, B). 



Anterior-margin setae thick, reddish bi-own, moderately long, intermediate 

 seta moderately long, lateral seta light, curved inward also moderately long; 

 anterior frontal seta procumbent, longer than lateral; intermediate frontal 

 seta situated near tentorial pit, small, thin; posterior frontal seta near 

 intermediate seta, short, thin; seta 7 situated ventral to antenna, brownish, 

 shorter than intermediate seta; seta 9 situated on ridge, moderately long, 

 reddish brown, larger than anterior-margin setae; seta 11 situated further 

 posteriorly, short, thin, near inner margin of periocular area; seta 10 

 similar, situated near anterior margin of periocular area; seta 14 at 

 posterior angle of periocular area, long, reddish brown, larger than 9; 

 seta 1? short, light, situated laterally at posterior margin of periocular 

 area; setae 15 and 16 situated close together behind seta 14, seta 15 light, 

 moderately long, 16 short, curved, brownish; seta 12 light, curved inward, 

 situated laterally behind 2 last-mentioned setae; seta 17 light brown, 

 m.oderately long. Ventral seta 8 small, strong, brownish; seta 18 smaller, 

 light, situated behind gula. 



* Described from specimens from the Zangi River (Georgia); this may be the larva of Micrasema 

 b i fo li a t u m Mart. 



493 



