the distal process; both setules are situated on the outer side; the trochantin 

 of the meso- and metathorax is also free, with a small dark seta. 



249 



FIGURES 252 and 253. Rhyacophila hokkaide nsis Iwata: 

 252 - abdominal segment, lateral; 253 - right anal leg, outer view. 



Forelegs slightly thicker and shorter than midlegs and hind legs; the 

 large setae are short, strong and black. 



Gills tufted; their stem is slightly longer than in Rhyacophila s. str.; 

 unlike in the preceding groups, the gills are situated dorsally, one tuft on 

 abdominal segment 1, three tufts on segments 2—7, one median tuft and two 

 lateral tufts; segment 8 with only two tufts (Figures 249, 252); the median 

 tuft of segments 1—7 is situated posterior to the laterally displaced medio- 

 anal seta; the lateral tufts of segments 2—8 are situated anteriorly and 

 posteriorly, near the base of the anterior -angle seta, on the boundary with 

 the pleural region. Dorsal sclerite of segment 9 reddish brown, lighter 

 in the middle than laterally; medioanal and anterior-angle setae black and 

 strong; there are two long setae, one on a light spot at the margin of the 

 sclerite and the second on a membrane near the sharp posterior angle of 

 the sclerite; intermediate and lateral setae small, thin, situated near the 

 margin of the sclerite. 



Anal legs relatively short (Figure 253); grooves of sclerite "b" blackish; 

 basoventral hook massive, black, slightly curved; ventral seta near the base 

 of the hook thin and situated on a sclerotized dot; a sword- shaped process 

 absent, replaced by a small dark process; both setae on the distal part of 

 the sclerite black, of the same length; distal seta of the basal part short and 

 strong; seta of the median sclerite of section "c" small and dark. 



264 



