272 Sclerite of pleuron of prothorax large; epimeral region near the pleural 

 suture weakly sclerotized; episternum continuous and light; trochantin 

 large, with a long hornlike process and a strong, long seta; both setules 

 situated at the base of the process (Figure 302). 



Pleuron of meso- and metathorax consists of a longitudinal and trans- 

 verse sclerite; the longitudinal sclerite is broader than the transverse 

 sclerite, which is very narrow; seta of episternum relatively large; small 

 seta of epimeron situated on a membrane. 



Legs short. Forelegs (Figures 302—304) more massive and slightly 

 longer than midlegs and hind legs. Coxae short, broad at base; both antero- 

 dorsal setae close together, short, strong and situated near the margin of 

 a deep, distodorsal notch; basal seta situated at a marked distance from 

 base of segment; posterodorsal seta long and thin; both anterior surface 

 setae small and strong; distoventral setae thin and small; posterior seta 

 larger than anterior seta. 



Trochanter with an oblong distal part; anterior seta short and strong; 

 posterior seta is similar but thin; distal anteroventral seta, forming a 

 small thick spine; middle and basal setae small and strong; basal seta 

 situated near the suture; the subapical posteroventral seta long and dark; 

 the 2nd seta small and thin. 



273 Femur short and massive, with short rows of minute spinules which are 

 better marked near the ventral margin. Basodorsal seta situated basal to 

 the middle of the segment, short and thick; distodorsal seta thin and 

 relatively long; thin posterior seta situated subapically; anterior seta 

 situated at a distance from the margin, short and strong; posteroventral 

 seta long and thin; anteroventral seta short and spinelike. 



Tibia and tarsus with similar minute spinules but are sparser. Both 

 distodorsal setae of the tibia thin; the posterior seta long and the other 

 short; anterior surface seta divided (Figure 305), small and stronger than 

 the thin posterior seta; both ventral setae thin; posterior seta longer than 

 the small anterior seta. The setae on the tarsi are situated distally; the 

 anterodorsal seta larger and stronger than the posterior seta; the antero- 

 ventral seta smaller than the posterior seta. 



Claw weakly curved; seta strong and spinelike (Figure 306). 



Midlegs thinner than the hind legs, both legs of about the same length. 



Abdominal segment 1 much shorter than the following segments; 

 anterior-margin seta of segments 1—8 small and distinct; anterior-angle 

 seta of segments 2—8 long and strong, as on the meso- and metathorax; 

 medioanal seta similar; intermediate and lateral seta small and thin. 

 275 One of the ventral setae is relatively large. The sclerite of segment 9 

 forms a thin sclerite (Figure 307); it has a narrow reddish brown border 

 near the anterior margin; posterior margin of sclerite is thinner; median 

 notch of the posterior margin hardly marked; lateral lobes widely separated, 

 pale yellow near the posterior margin, with strong, long median and 

 anterior-angle setae laterally; intermediate and lateral setae situated 

 between them short and thin, light brown and relatively large. 



Anal legs of characteristic structure; dorsolateral sclerite "b" (as in 

 Rh. lata and Rhyacophila sp. "y") (Krawany, 1935:246— 247) without 

 a basoventral hook; instead of the hook, the ventral side bears a curved, 

 pointed process at the black basal margin; the distal part of the sclerite 



294 



