468 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 113 
18(17). Head darkest anteriorly, paling gradually posteriorly. 
(mycta?) species 4 
Head not as above, generally with an indistinct pattern (fig. 8,a,c). . 19 
19(19). Frontoclypeus narrowing ee to posterior point (fig. 8,c); head 
nearly black dorsally. . . . . . shenandoahensis 
Frontoclypeus narrowing more Ooeaaealiy Gls ete head only slightly 
darker; dorsally 2). » GAdisnrs Leas ee O 
20(19). Anal claw with a second contre Heel Ge 8 ie Js +) ae vara 
Anal claw generally lacking second ventral tooth (Gig. 8,d). . . .vibox 
Rhyacophila fuscula (Walker) 
Ficure 1 
Neuronia fuscula Walker, 1852, p. 10. 
Rhyacophila fuscula (Walker) Lloyd, 1921, p. 112 (larva).—Betten, 1934, p. 130 
(male and female genitalia, larva)—Ross, 1944, p. 36 (male and female 
genitalia, larva). 
This is the commonest species of Rhyacophila found in eastern 
North America. It is known from almost all the states and provinces 
west to Michigan and south along the mountains into Georgia. 
Figure 1.—Rhyacophila fuscula: a, mandibles, dorsal aspect; b, anal proleg, lateral; c, head 
and pronotum, dorsal. 
