anterior-angle setae; intermediate seta thin, brown, very long; lateral 

 seta small, light; 2 thin, strong, moderately long setae between medioanal 

 setae; surface with 8—9 short, and small, secondary setae. 



Sclerite "b" of anal legs brown; lateral dots large, not very distinct; 

 large setae black; mediodistal seta long; neighboring seta slightly 

 shorter; lateral seta thinner, of moderate length, separated from other 2; 

 a similar and a short, thin seta at median margin; ventral seta strong, 

 short; surface with 9—10 small, thin setae. 



Sclerite "c" brown, with broad, black, lateral margin; basal seta small, thin. 



Claw brownish yellow, dark brown apically, with a large dorsal denticle; 

 setae 1 and 3 darker and thicker than others. 



Case 12—21 mm long, with smooth surface, curved greatly narrowed 

 posteriorly, made of small sand grains, often including plant fragments 

 (Figure 407). 



Pupa. Length 10— 14 mm. Antennae reaching abdominal segment 7—8. 

 Labrum with rounded anterior margin. Distal part of mandible relatively 

 wide, convex laterally; median blade straight, serrated. 



Wing sheaths reaching abdomonal segments 4—5. Mid tarsi with 

 natatorial setae; hind tarsi with sparse setae on segments 1—3. 



Dorsal process of abdominal segment 1 slightly dark, posterior spinules 

 small, few. Gills on segments 2—8. Holding apparatus on segments 3—7; 

 number of hooks: 111:1-2; IV:2-3; V:2-4+7-15; VI:2-4; VIl:2-4. 



Anal rods 0.7— 1.0 mm; 1st seta situated in basal quarter, 2nd seta in 

 middle or more apically, 3rd and 4th seta subapically and apically. Sheaths 

 of ventral appendages of male wide, large; lobes of penis sheath of same 

 length incised posteriorly (Figure 408). 



Case 12—17 mm long, made of sand grains or sand grains and plant 

 particles; anterior and posterior membranes with numerous holes; case 

 covered with moss or other plants; anterior and posterior end of case 

 attached to plants. 



Mode of life and habitats. Usually small, stagnant water bodies, 

 calm, overgrown littoral of lakes. 



Distribution. The European USSR, including the Crimea, Altai, 

 Sayans. In addition, Europe, Asia Minor. 



Number and arrangement of gills of L. g r i s e u s 



Segment 



Dorsal 



Pleural 



Ventral 



2 



3 

 3 



2 



3-2 



3-2 

 3 



3 



3 

 1 



3 



2-1 



3 

 3 



4 



3 



2 



2-1 



1(0) 



3 



2 



5^ 



2 

 2-1 







2 

 2 



6 



2-1 

 2 







2-1 

 2 



7 



2-1 

 2-1 







1 

 1 



8 



1 (0) 









289 



