margin brownish and thin. As in H. ornatula, sclerite "c" strong, reddish 

 brown, with a thick, straight, dark brown seta and several small setae near it. 



Claw (Figure 696) dark brown; setae distinct; basodorsal seta 1 

 moderately long, light and thin; seta 2 directed upward and slightly outward, 

 longer, thicker and brownish; setae 3 and 6 at sides of the apical part brown, 

 longer than the others; seta 8 at basal part thin, light, curved, longer than 

 the straight, brownish, thicker seta 7; straight, short, thin, brown seta 5 on 

 495 the outer side near seta 8; small seta 4 situated near margin of the 

 transverse stripe. 



FIGURES 696-698. Hydropsyche angustipennis Curt.: 



696 — claw of left anal leg, outer view (A), of right anal leg, inner 

 view (B); 697 — labrum of young larva (1st stage) (after Siltala); 

 698 — anterior end of pupal case from inside, with openings of the 

 membrane. 



Young larva. First stage. Length 1.8— 2.5 mm; length of head and 

 prothorax are the same at beginning of this stage; ratio of length of head 

 thorax and abdomen 1:1.8—2.2:3.2—3.5 at beginning of stage, and 1:1 .6—1 .8:5.6 

 at end of stage (Siltala, 1907:413—416); broadest part of body is the head at 

 the beginning of the stage, and first abdominal segments are broadest parts 

 at the end of the stage. Only the mandibles are brown in the freshly hatched 

 larva: head and pronotum become yellowish brown or brownish at end of 

 the stage; other sclerites paler; margin of sclerites dark in some places. 

 Head sutures absent at beginning of stage; they become distinct at end of 

 the stage. 



565 



