Pronotum (Figure 785, A) yellowish brown, with large, indistinct, 

 brownish, lateral pattern in form of a wide bracket; 2 small, pinkish brown 

 streaks near median suture; large and small, pinkish brown dots in each 

 half; posterior margin mainly light, with large, chestnut brown, lateral 

 areas with dark outline. Mesonotum (Figure 785, B) slightly lighter; 3 dots 

 at anterior margin in each half; one dot near the median suture; a number 

 of large and small, pinkish brown dots in a curved row on the surface. 

 Chaetotaxy as in T.bicolor. 



Propleuron: trochantin lobe-shaped with rounded distal part and almost 

 straight anterior margin; seta subapical, large, strong, light. 



Forelegs brownish, darker than mid- and hind legs. Hind legs yellowish 

 brown; tibia divided; femur shorter and thicker than tibia; tarsus un- 

 divided, narrow, slightly shorter than tibia. 



Dorsal process of 1st abdominal segment high and large as in 

 Mystacides and Triaenodes; area with spines on lateral processes 

 yellowish, with a distinct, slightly darker stripe at posterior margin; dark 

 sclerite absent. Gills absent. 



Tergite of abdominal segment 9 whitish, indistinct, with small, pinkish 

 brown dots; submarginal setae dark brown, as in T.bicolor; median 

 setae long; lateral and anterior- angle setae shorter, the latter slightly 

 thinner; intermediate seta and anterior-margin seta short, thin. 



Anal legs relatively long, as in T.bicolor; sclerite "b" white, with 

 brownish, basal dots, with dark brown setae apically; 3 long, thick, distal 

 setae at the base of the claw; a moderately long, strong seta further basally 

 and laterally. Claw small, reddish, with 2 dorsal denticles. 



Case 9— 10 mm long, straight, slightly narrower posteriorly made of 

 small plant fragments arranged in regular rows as in T r ia en od e s , but 

 in oblique semicircles, not spirals; the opposite semicircles meet in an 

 irregular zig-zag line dorsally and ventrally (Figure 786); posterior end 

 open, as in Triaenodes, without membrane. 



Pupa. Length 8.0— 8.5 mm. Gills absent. Holding apparatus on segments 

 3—6; number of denticles; III: 3—4; IV: 3—4; V: 4+ 7—9; VI: 4. Anal rods 

 (Figure 787) long, nearly uniformly thin, with very short distal part and with 

 4 small setae. 



Case as in larva, 8 — 10mm long; anterior membrane with round central 

 hole; posterior membrane with an elliptical, transverse slit. 



Mode of life and habitats. Small, often m.arshy stagnant water 

 bodies. 



Distribution. Western and northwestern parts of the European USSR. 

 In addition, inainly Central and Northern parts of Europe. 



6. Genus Leptocerus Leach (Se to d e s McLachlan, 1884, partim 

 group 1) 



Full-grown larva. Length 8— 10mm. Head oblong; pattern consisting 

 mainly of dots; white lateral stripes distinct. Gula triangular; gular and 

 coronal suture absent. Pronotum. and mesonotum sclerotized; hind legs 

 natatorial in some species. Gills absent. Tergite of abdominal segment 9 

 absent. Claw with a large, dorsal denticle, sometimes with 3 denticles. 

 Case made of secretion or with a few fine sand grains. 



613 



