pebbles" differ in form from the others and are firmly attached to the basal 

 tissue; posterior end covered by a membrane with an irregular hole, 

 usually with 1 or 2 small sand grains. The case of the earlier stages 

 is relatively wider and without characteristic form; a lateral row of small 

 stones appears only in 4th stage larvae. 



Pupa. Length 5.4— 8.7 mm. Antennae reaching end of body; antennal 

 segments 1—2 with a tuft of setules. Labrum (Figure 2 39) with median 

 process, and separated from anteclypeus by lateral indentations. 

 Anteclypeus with thin setae; lateral seta short, 2 other setae slightly 

 longer. Anterior -margin seta of labrum relatively large; labrum with 

 5 other setae, 3 of them thick and long, 2 thin, moderately long; all of them 

 with hooked end; median pit of labrum asymmetrical, displaced to the left. 



Mandibles (Figure 240 ) long; median blade flat distally, concave, 

 serrated, with dense, small spinules at margin more basally; lateral 

 setae small, almost of same length, dorsal seta thick, ventral seta much 

 thinner. 



Wing sheaths reaching posterior end of abdominal segment 4 or 5. 

 Midlegs of natatorial type; setae thin, pale, situated dorsally near apex of 

 tibia and on tarsal segments 1—4, ventrally on tarsi only, last 2 segments 

 with small and delicate setae. 



Abdominal segment 1 with lateral processes covered with small spinules. 

 Holding apparatus on segments 3—7; number of spinules 111:3—5; IV: 3— 5; 

 V:2-4+5-8; VI:2-3; VlI:2-5. Lateral line pale, on segments 5-8. 



Anal rods (Figure 241 ) thin, curved at end, with small brown spinules; 

 2 setae in proximal and 2 in subapical part, seta near base of gill smaller 

 than others. 



Pupal case (Figure 242) attached to a stone at anterior end so that a 

 strip of membrane with 14—16 holes remains at anterior margin; a thin 

 membrane covers anterior area in contact with the stone; posterior 

 membrane with 2—4 small holes. Adults hatch by gnawing through upper 

 wall of case. 



Mode of life and habitats. Brooks with rapid current, 

 0.4— 0.8 m/sec, on stones. 



Distribution, Northwestern areas of USSR, rare.* In addition, 

 Europe. 



9. Apatania auricula Forsslund 



Kachalova, 1961 : 199-203, Figures 1-3. 



Full-grown larva. Length 8 mm. Head (Figure 243) almost uniformly 

 light brown, slightly darker in some places; light punctation in posterior 

 part of frontoclypeus and lateral to coronal suture; eyes on a large 

 yellowish spot. Ventral side of head brownish; gula in form of narrow 

 triangle. 



Labrum yellowish, with dark stripe at posterior margin, without dark 

 punctation. 



The collections of the Zoological Institute of the USSR Academy of Sciences contain 4 specimens from 

 Lopukhinka near Leningrad, collected in August 1894 by L. V . Bianki, and determined by A. V. Martynov. 



175 



