Sclerite "c" yellowish, brownish laterally, with brownish lateral 

 margin; basal seta short, dark. 



Claw yellowish brown basally, dark, brownish apically, with a dorsal 

 denticle flanked, usually, by 2 thick spinules on each side; setae as in 

 H. m agnu s . 



Number and arrangement of gills of H . n i g r o v i 1 1 a t u s 



Segment 



Dorsal 



Pleural 



Ventral 



2 











3 





1 







4 





1 







5 





1 







6 







1(0) 





7 



1(0) 









8 









1(0) 



Case 30 — 42 mm long, made of detritus, smooth if made of small par- 

 ticles; cases made of large fragments are bulky, as in H. magnus, with 

 a rough surface, often with long rods projecting beyond posterior end; 

 anterior end often with a number of smoothly arranged sand grains ventrally 

 or all around; whole anterior part or most of case sometimes consists of 

 sand grains (Figure 492). 



Pupa. Length 21—22 mm. Antennae reaching end of segment 6 or 

 beginning of abdominal segment 7. Lab rum brownish, with a small, light 

 spot with 5 reddish brown hooked setae; seta 1 small, situated lateral to 

 median process at anterior margin, light, relatively large. 



Mandibles dark brown; blade of distal part serrated; lateral setae 

 brown, dorsal seta larger than ventral. 



Wing sheaths reaching abdominal segment 4. Natatorial setae light, 

 dense, grayish, on segments 1 —4 of mid-tarsi; hind tarsi with sparse 

 light setae, those of segments 1 and 2 larger and denser, those on following 

 segments slightly smaller. 



Process of abdominal segment 1 wide, light, with fine transverse stria- 

 tion; saddle-shaped distal margin with reddish margin with relatively large, 

 dark brown setae. Holding apparatus on segments 3—7, number of hooks: 

 III: 6-7; IV: 7-8; V: 8-10 +16-20; VI: 6-8; VII: 5-6. 



Anal rods thicker in basal part, club-shaped apically; setae dark, basal, 

 subapical, and apical setae slightly larger than in P o t am o p hyl ax ; seta 

 in middle small. 



347 



