88 THOMAS SAY FOUNDATION 
femur, brown, and the femora with another transverse brown 
band just before the apex. 
Abdominal segments normally with their basal half yellowish, 
and the posterior half dark brown to blackish. In some of the 
more darkly colored specimens the segments are almost entirely 
brown or blackish, with only the median portion of the basal parts 
yellowish. Cerei composed of about fifty segments and bearing on 
the inner surface a fringe of long, fine hairs, which are longer 
and more dense at the base than beyond. Entire surface of the 
nymph covered with a fine coating of brownish hairs, except the 
head, which is quite smooth. 
Gills and the mouth parts as in A. abnormis. Anal gills absent. 
These nymphs are commonly found in swift-running water under 
stones, and although little is known of their habits, they are of 
the carnivorous type, and apparently have a three-year life cycle. 
The narrow black band on the posterior margin of the tenth 
abdominal tergite readily distinguishes lycorias from related 
forms. 
Ithaca, N.Y.; Dansville, N.Y.; Lake George, N.Y.; Clinton, 
N.Y.; Ft. Ann, N.Y.; Guelph, Ont. 
Acroneuria pacifica Banks 
(Plate 5, figs. 71-76; plate 25, fig. 204; plate 32, fig. 224.) 
Length of body up to 23 mm.; antennae up to 19 mm.; cerci 
up to 11 mm. 
This is a western form and is most readily recognized by the 
blaze upon the head in front of the anterior ocellus. 
General color chestnut brown to dark brown, with lighter areas 
on head and thorax. 
Head a little narrower than pronotum, brown, with lighter 
areas on the occiput, and lighter spots on the outside of the hind 
ocelli, and with a whitish blaze extending forward from the an- 
terior ocellus as indicated in Plate 32, fig. 224. 
Pronotum a little more than twice as wide as long, somewhat 
convex on the anterior margin and slightly concave on the 
posterior one; lateral margins convex, angles broadly rounded ; 
marginal groove distinct near the anterior and posterior margins, 
but rather faintly noticeable on the sides, which are not produced 
into distinct flanges. 
Legs somewhat flattened, fringed thickly with long hairs. 
Abdomen somewhat depressed, brown, each segment with a 
round yellowish spot near the posterior border along the median 
