Wing sheaths narrow, pointed, reaching beginning or middle of abdominal 

 segments. Tarsi of all legs with natatorial setae, those of mid-tarsi more 

 numerous. 



Gills on abdominal segments 2— 8, with 1—3, rarely 4, filaments. Holding 

 apparatus presegmental on segments 3— 6, postsegmental on segment 5. Anal 

 rods straight, close together, with short setae. 



Case as in larva; winglike extensions narrower, as larva ceases to make 

 them before pupation; pupa lies with dorsal side downward; anterior cover 

 with a transverse slit at dorsal margin, posterior cover with a slit at ventral 

 margin. 



Mode of life and habitats. Lakes; sandy littoral, on slightly- 

 silted, overgrown bottom; near river mouths. 



Distribution. Throughout the USSR, except for Middle Asia and the 

 Caucasus. In addition, Europe, China, Japan, India, Ceylon, Sunda Islands, 

 North America. 



Key to Genera 

 Full-grown larva 



1 (2). Length 12 — 15 mm. Dorsal side of head and pronotum with 



characteristic pattern of stripes and dots. Claw of hind legs short, 

 blunt. Gills with 1—3, rarely 4, filaments. Case made of sand grains 



or sand and detritus; wings of case well marked 



1. Molanna Curt. (p. 523) 



2 (1). Length 9— 10 mm. Dorsal side of head and pronotum mainly dark. 



Claw of hind legs long, thin. Gills with 1—2 filaments. Case made of 



detritus, with small wings, almost flat ventrally 



2. Molannodes McL. (p. 535) 



1. Genus Molanna Curtis 



Full-grown larva. Large, with distinct pattern on head and pronotum. 

 Transverse suture of mesonotum distinct, or indicated by a row of dots. Gills 

 with 3—4 filaments. Case shield-shaped, with wide, winglike extensions; 

 tube distinct ventrally. 



Mode of life and habitats. Calm littoral zone of lakes, river 

 mouths, on a bottom of sand or sand and silt, at a depth of 0.5 — 3.0 m, 

 sometimes deeper in upper sublittoral; often among vegetation. 



Distribution, The European USSR, Siberia, the Amur Region. 

 In addition, Europe, India, China, Japan, North America. 



418 Key .o Species 



Full-grown larva 



1 (4). Frontoclypeus with light posterior angle. 



523 



