sides of the middle; sides of anterior part with two large dots; the dark 

 background of the posterior part with a curved row of dots which are large 

 in the middle and small laterally. Of the 3 anterior-margin setae, the seta 

 lateral to the frontal suture is light, curved anteriorly; intermediate seta 

 thin, small; median and anterior frontal seta recumbent; middle frontal 

 seta straight, small; posterior frontal seta thin and long. Dorsal stripes 

 closely adjacent to the frontal sutures, wide posteriorly; the space in the 

 posterior part, lateral to the epicranial suture remains light; stripes with 

 large dark dots; lateral stripes slightly dark and with small dots. The 

 large setae on the head are thin and brown; they are very thin at the end; 

 seta 7 situated on the anterior margin; seta 9 long; posterior to it, nearby, 

 is the small thin seta 11; seta 14, which is almost as long as seta 9, is 

 situated posterior to the eye; lateral to it stands the shorter seta 12; 

 farther posteriorly are the thin yellowish seta 15 and the large brown 

 seta 16 behind each other; lateral to these setae stands the small, thin 

 seta 13; seta 17 is situated near the bifurcation of the suture and is small 

 and light; the small ventral seta 8 is situated at the posterior margin; 

 seta 18 is situated in the anterior part of the head; the large setae 8 are 

 situated at the sides of the gula (Figure 274, B). 



Labrum (Figure 2 75) short and broad; its dorsal sclerite is golden 

 yellow and thin, its membranous border broad; sides of labrum with white 

 hairs; median notch shallow; seta 1 situated on the membrane and light, 

 setae 2 and 5 situated on the margin of the sclerite and long; setae 4 

 situated on the sclerite at the sides of the median notch; they are short 

 and light; seta 3 situated on the side of the sclerite; it is light and 

 recumbent; seta 6 is situated near seta 3; it is yellowish brown and long. 



[259) 



FIGURES 274 and 275. Rhyacophila sibirica McL.: 

 274 — head, dorsal (A) and ventral (B); 275 — labrum, dorsal. 



276 



