2 79 3. Genus Stenophylax Kolenati 



Full-grown larva. Brownish, lighter than in other genera of the tribe. 

 Pattern consisting of dark, large dots; large setae black. Gills on 

 segments 2—8. Case straight, smooth, made of detritus. 



Mode of life and habitats. Brooks with moderately rapid 

 current. 



Distribution. Southern part of the European USSR. In addition, 

 Europe, except northern counti'ies; Noi-th Africa, Iran. 



1. Stenophylax perinistus McLachlan 

 Fi'ochot, 1962:1-16, Figures 1-13. 



Full-grown larva. Length 18— 20 mm. Head (Figure 495) relatively 

 wide, pale i-eddish brown; punctation distinct, brown; only primary setae 

 present; setae 9 and 14 larger than others, black, thick. Gula slightly dark. 



Thoracic tergites as in Figure 496. Pronotum yellowish brown; groove 

 in anterior third slightly darker; posterior margin blackish; punctation 

 dark, distinct; setae brown or reddish brown, strong. Mesonotum yellowish 

 brown, yellowish at posterior angle. Lateral tergites of metathorax pale 

 posteriorly. 



Legs brown; form and chaetotaxy of legs as in Potamophylax 

 stellatus. 



Abdominal segment 1 darker than other segments; median ventral 

 process wide, with 30—50 small, dark setae. Lateral line on segments 3—8. 

 Gills on segments 2—8. 



Tergite of segment 9 brown, with a row of blackish brown dots at anterior 

 margin; medioanal setae longer than others, black; anterior-angle setae, 

 intermediate setae, and secondary seta between medioanal setae dark, strong 

 but shorter; surface with 8—9 small setules. 



Number and arrangement of gills of S. permistus 



Segment 



Dorsal 



Pleural 



Ventral 



2 





1 



1 





3 





1 



1 





4 





1 



1 





5 





1 (0) 



1 (0) 





6 





1 (0) 







7 









1(0) 



8 





• 





1(0) 



350 



