Lateral line on segments 3— 7, indistinct, with small, pale hairs; segment 

 8 without sclerotized dots. Gills single, with a thick, long filament on 

 segments 2 — 8 dorsally and ventrally at anterior margin; segment 2 also 

 with a lateral gill at posterior margin. 



Tergite of segment 9 (Figure 803, A) large, brown, sometimes darker at 

 anterior margin; posterior margin laterally with 16—17 setae, including a 

 thick, long, black, medioanal seta; 3—4 similar large, thick setae among the 

 strong, golden brown other setae. 



Sclerite "b" of anal legs brownish, narrow; setae at distal margin thick, 

 black, 2 — 5 long setae above claw and 3 short setae, including a subapical 

 seta at median margin and 2 lateral setae. Sclerite "c" with a short, thin, 

 brown seta. Claw reddish, small, with 2 — 4 dorsal denticles (Figure 803, B). 



Case (Figure 804) slightly curved, tapering posteriorly, made of sand 

 grains, sometimes also with silt particles, smooth; ventral surface slightly 

 flat, made of smaller grains. 



80^ 



805 



FIGURES 803-805. Oecetis o chra c ea Curt. : 



803 - posterior part of abdominal segment 9 CA), claw of anal leg fB); 804 - larval 

 case; 805 — pupa: labrum and anteclypeus (A), left mandible, ventral (B), lateral 

 process of 1st abdominal segment (C),anal rods (d). 



631 



