332 



333 



Case closed, attached to the substrate with its narrow ventral side, 

 attached by ligaments at the anterior and posterior end; there are often 

 numerous specimens on stones or plants. 



Mode of life and habitats. It occurs mainly in running water, 

 in brooks and rivulets with a rapid or slow current; on stones, parts of 

 trees or thickets; rare in lakes. 



Distribution. European USSR, Caucasus, Middle Asia. In addition, 

 Europe, Africa, North America, Japan, Australia. 



Key to Species 

 Full-grown larva 



1 (2). Labrum with a broad, dense fringe of thin hairs at the anterior 



margin 1. H. femoralis Eat. (p. 365) 



2 (l). Labrum without a fringe at the anterior margin. 



3 (4). Head of almost uniform color, slightly darker only posteriorly . . . 



3. H. maclachlani Klap. (p. 371) 



4 (3). Pattern of head distinct. 



5 (6). Sclerotized parts of body generally light; frontoclypeus dark only 



anteriorly; a small, dark area dorsally, near the occipital foramen; 



thoracic sclerites slightly dark or mainly light 



4. H. pulchricornis Pict. (p. 373) 



6 (5). Sclerotized parts of body generally dark; whole dorsal surface of 



head, except the light spots around the eyes dark; pronotum mainly 

 dark brown; brown anteriorly and laterally; meso- and meta- 

 notum dark brown laterally and in the middle; brown in the anterior 



and posterior parts, except the darker median area 



2. H. sparsa Curt. (p. 371) 



1. Hydroptila femoralis Eaton 



Siltala, 1904b:12-15, Figure 3, a-f . - Ulmer, 1909:224, 292.- Nielsen, 

 1948:62-76, Figures 3, G, 4, B, 6, B, G, 7, A, B, 18-25. 



Full-grown larva (Figure 411). Length at the beginning of the stage 

 1.8 mm, at the end of the stage 3.7—4.1 mm; width of head 0.19— 0.23 mm; 

 ratio of length of head, thorax and abdomen at the beginning of the stage 

 10:19:35; at the end of the stage 10:19:91. 



Head relatively small; prothorax slightly broader than head; 1st ab- 

 dominal segment slightly higher than metathorax. 



Head (Figure 412) with strongly convex dorsal surface; head oblong in 

 dorsal view dark brown; a large, light spot, which occupies a large part of 

 the surface near the eyes; antennae shown in Figure 413. Ventral surface 

 of head lighter than dorsal surface. The lateral, anterior margin seta of 

 the frontoclypeus is thin, curved inward; the intermediate seta is the longest; 

 the anterior and posterior frontal setae are also curved inward; middle 

 seta long. Seta 9, which is the longest seta of the head and the small 

 adjacent seta 11 slightly displaced posteriorly to near the posterior margin 



365 



