Key to Genera 

 Full-grown larva 



1 (2). Dorsal side of head black or brownish black in middle; mesonotum 



with 3 pairs of sclerites, metanotum with 4 pairs; case with coarse 

 sand grains laterally, as in Apatania. Western part of the 

 European USSR, the Caucasus 3. Lithax McL. (p. 433) 



2 (1). Dorsal side of head brown or reddish brown; number of tergites on 



mesonotum and metanotum similar or smaller; case with small 

 stones laterally, attached at margin. Widely distributed. 



3 (4). Frontoclypeus large, anterior and posterior parts well developed, 



posterior part narrower; mesonotum with 2 pairs of sclerites; 

 metanotum with 3 pairs of small sclerites as in Limnophilinae .... 

 1. Goera Steph. (p. 406) 



4 (3). Anterior part of frontoclypeus large, broad; posterior part much 



narrower and shorter; mesonotum with 3 pairs of sclerites, meta- 

 notum with 4 pairs 2. Silo Curt. (p. 416) 



1. Genus Goera Stephens 



Full-grown larva. Medium-sized, 12 — 14 mm long. Head light brown or 

 reddish brown dorsally, flat in middle, without tubercles, in some places, 

 surrounded by a ridge. Mesonotum with 2 pairs of sclerites, metanotum 

 with 3 pairs. Case with several small stones laterally, attached at margin 

 and with winglike lobes. 



Mode of life and habitats. Slow brooks and rivulets, open shore 

 of lakes with moderate surf, on solid bottom. 



Distribution. Parts of the European and Asian USSR. In addition, 

 Europe, Asia, North America. 



Key to Species 

 Full-grown larva 



1 (2). Dorsal side of head brownish, its median, flat area lighter, surround- 



ing ridge distinct only anteriorly; ventral surface whitish, with a 

 broad chestnut brown stripe posteriorly and near gular suture; 

 gula triangular, relatively wide. Tergites of mesonotum light brown, 

 with indistinct punctation 1. G. pilosa Fabr. (p. 407) 



2 (1). Dorsal side of head reddish brown, including flat, median area; 



surrounding ridge distinct laterally, formed by dense, blunt tubercles; 

 ventral surface reddish brown; gula oblong, narrow, with blunt, 

 324 truncate posterior end. Tergites of mesonotum reddish brown, 



with distinct, dark dots 2. G. sajanensis Mart. (p. 412) 



406 



