1. Rhyacophila hokkaidensis Iwata 



Iwata, 1927a:203-204, Figure A, 2, 18-25. 



Full-grown larva (Figure 249). Length 18— 19 mm. Head oblong, 

 yellowish; frontoclypeus dark in the anterior part and laterally, light in 

 the middle of the posterior part; posterior angle with two large dark dots; 

 dorsal stripes well marked from the anterior margin, narrow in the anterior 

 part; they are broader posteriorly, extending to the bifurcation of the frontal 

 suture; lateral stripes absent, replaced by dark dots; the space between the 

 stripes light or slightly dark. Ventral side of head light (Figure 250); each 

 half with groups of 2—3 distinct dots and several indistinct dots lateral to 

 seta 8. 



FIGURES 250 and 251. Rhyacophila hokkaidensis Iwata: 

 250 — head, ventral; 251 — left margin of pronotum and propleuron. 



The left mandible without teeth; lower blade finely serrated; right 

 mandible with two teeth in distal part; the basal tooth of distal part forms 

 a small process. 



Pronotum (Figures 249, 251 ) with a broad dark posterior margin; 

 lateral margin narrowly black in the posterior half; there is a dark figure 

 which is broader in the middle in the anterior part; the anterior part bears 

 a curved row of dots lateral to the figure; posterior part with groups of dots; 

 the primary anterior -angle seta and one of the secondary anterior -angle 

 setae long; 2nd secondary seta thinner, moderately long and well 

 developed. The primary anterior-angle and the medioanal setae of the 

 meso- and metanotum are thin and long, as on the abdominal segments. 



Propleuron (Figure 251) with a broad pleural suture; the epimeron forms 

 a narrow brownish stripe close to the suture; the seta is small, situated 

 on a membrane; episternum brownish; trochantin oblong, not fused with 

 the episternum and darker; the seta is short, black, situated at the apex of 



263 



