Covering setae mostly dark, blunt, relatively long, interspersed anteriorly 

 with brown, setuliform, pointed spinules and small, light, hairlike spinules; 

 membranous margin with long inward -curved tufts of grayish brown, strong 

 hairs arranged in fans near the angles. Seta 5 light brown, straight, 

 directed anteriorly; the short, transparent seta 4 situated more medially, 

 492 near the margin; 3 straight, thin, transparent setae at the margin, the lateral 

 of these setae very small. 



(49i; 



FIGURES 690 and 691. Hydropsyche angustipennis Curt.: 



690 - frontoclypeus (after Siltala); 691 - labrum, dorsal (A), covering setae (B). 



Both mandibles (see Figure 89) with 2 apical teeth; upper blade of left 

 mandible without teeth, lower blade with 4 teeth; basal tooth blunt and broad, 

 the other 3 teeth of the left mandible, of the same size; tooth near the basal 

 tooth on the right mandible projecting and much longer than the others; 

 chetoids of median brush of left mandible straight, thin, relatively long; 

 outer surface of mandibles with dark brown, marginal ridges, setae on the 

 surface light, mainly short; both primary setae situated in about the middle, 

 moderately long, one near the dorsal ridge, the other slightly posteriorly. 



Submentum yellowish, with a dark median stripe; lobes dark brown; 

 6 setae of the oblique basal row dark, strong, 2 of these longer than the 

 others; several small dark, light setae near the row; surface setae of lobes 

 brown, and both short and relatively long; lateral primary seta near the 

 base longer than the others. Cardo golden brown; 20—22 setae at base and 

 on outer side brown, the primary seta situated among them; stipes with a 

 reddish brown, longitudinal, dark stripe; tufts of setae, including a primary 

 seta on the outer side distally and basally. Palpifer and palps light brown; 

 apical seta of palpifer grayish, relatively thick, straight; mediobasal seta 

 very small, transparent, light, situated near the base; galea adpressed to palp, 

 dark brown with long setae and sensillae. First segment of palp twice as 

 long as the 2 following segments; last segment narrower, longer than the 

 preceding segment, with short sensillae. Mentum light yellow, dark brown 

 laterally; ventral sclerites small, light, round, with a transparent seta; 

 horseshoe-shaped sclerite of labial palpifer yellow; palps very small, 

 situated lateral to the large opening of the spinning glands. 



561 



