II. Family GLOSSOMATIDAE Wallengren 



Full-grown larva. Length 5—12 mm. Head broad and short, slightly 

 lower than broad; dorsal surface larger than ventral surface. Fronto- 

 clypeus broad and long; lateral notches in the anterior half of the sclerite 

 shallow. Eyes situated on light spots at the level of the lateral notches of 

 the sclerite. Antennae situated anterior to the eyes some distance from the 

 anterior margin, with 2 sensillae and 2 setules, one of them short and the 

 other long. Dorsal setae displaced to the anterior part of the head, to the 

 periocular area. Labrum broadly membranous anteriorly. Mandibles 

 without teeth; left and right mandible with brushes in the middle; a group 

 of feathered chetoids among the chetoids. 



Pronotum wide, convex; prosternum well developed. Meso- and meta- 

 thorax membranous dorsally or with small paired tergites; pleural sclerites 

 large. 



Legs thin and short. 



Abdominal segments subcylindrical; tergite of segment 9 large, 

 trapezoidal. Six anal gills. Anal legs short and massive, obliquely directed 

 downward, with a small strong claw. 



The larvae live in cases with a rooflike dorsal surface and a flat ventral 

 surface. 



Pupa. Length 3— 8 mm. Antennae reaching the abdominal segments 5—8. 

 Labrum with almost straight anterior margin; anteromedian seta much 

 smaller than the 6 other setae. Mandibles symmetrical, with two teeth. 



Presegmental plates of the holding apparatus on segments 3—7 or 4—7; 

 postsegmental plates on segments 4 or 4 and 5. 



Mode of life and habitats. Brooks, rivulets and rivers with 

 clean water and currents of varying strength; mainly in rapid currents; 

 on stones. 



Distribution. USSR: European and Asian parts of the Soviet Union, in 

 hilly and mountain landscapes. In addition, Europe, Asia, North and Central 

 America, partly Africa and Australia. 



Key to Subfamilies 

 Full-grown larva 



1 (2). Medium-sized, 8— 12 mm long; meso- and metanotum membranous 



without sclerites; claws of legs with a process at the base of 



the basal seta 1. Glossosomatinae Ulm. (p. 323) 



2 (l). Small, 6— 7 mm long or less; meso- and metanotum with small 



lateral sclerites; claws without process at the base of the basal seta 

 2. Agapetinae Mart. (p. 336) 



298 Pupa 



[2). Length 6— 8 mm. Outer setae of mandibles almost equally long; 



basal seta only slightly shorter. Presegmental plates present on 

 abdominal segments 3—7, postsegmental plates on segments 4—5. 

 Length of pupal case 8—11 mm ... 1. Glossosomatinae Ulm. (p. 323' 



322 



