fragments attached at anterior end; lateral walls of such cases are made 

 of small sand grains. 



Stage 4. Length 8.8- 15.0 mm. Width of head 1 .3 — 1 .4 mm. Punctation 

 more distinct. A median prothoracic sternite present. Secondary setae 

 more numerous. Gills on segments 2 — 6; lateral line present. Case made 

 of sand grains or plant fragments, sometimes anterior end with sand 

 grains, posterior end with plant fragments. 



(261) 



FIGURES 456-461. Potamophylax n i gr i c o r n i s Pict. (after Nielsen): 



456 - 1st stage larva, dorsal; 457 - case of 1st stage larva (A), 3rd stage 

 (B), and 5th stage (C, D, E). Pupa; 458 — anteclypeus and labrum; 459 — 

 left mandible, lateral; 460 — posterior end of male pupa, ventral (A), left 

 anal rod, dorsal (B); 461— case. 



Pupa. Length 16 — 17 mm; male pupae slightly smaller than female. 

 Antennae of male pupa reaching abdominal segment 9; scape with one seta, 

 pedicel with 4 — 9 small setae. Anteclypeus short, separated from labrum 

 by a deep groove; lateral seta of anteclypeus small, 2 other setae dark, 

 strong. Labrum (Figure 458) relatively long, brownish in middle, anteriorly, 

 and on part of sides; sides almost straight, median process rounded; seta 1 



327 



