PLECOPTERA NYMPHS OF NORTH AMERICA 87 
proximal end of tibiae brown; outer margin with a fringe of 
long hairs. 
Abdomen flattened ; basal half of tergites usually darker brown 
than caudal half; tenth tergite usually brown except for a small 
oblong yellow spot in the center; surface covered with brown 
hairs; each segment with a fringe of short spinules; cerei more 
than half as long as body and made up of forty or more seg- 
ments (tips broken off). 
Gill tufts as in A. californica, except that this species has, in 
addition to the thoracie gills, a pair of large anal gill tufts. 
The mouth parts are very similar in structure to those of A. 
californica. 
The above description is made from four specimens; two im- 
mature nymphs and a east skin from Left Branch, Provo River, 
Logan, Utah, July 28, 1926, J. G. Needham; and one almost 
mature nymph which bears the label Nez Perces Cr., above Basin, 
Rocky ‘‘ripples,’’ Aug. 15, 790, 26918. 
It was at first thought that these nymphs might belong to the 
genus Perla, because of the distinct occipital ridge, but the large 
ocelli, the general structure, and the faint indication of a ‘‘ham- 
mer’’ on the ninth abdominal sternite of the male nymphs in- 
dicate that they very probably are the nymphs of A.. depressa. 
wyopne”? 
; : car?’ 
Acroneuria lycorias Newman yg? Sion 5 SOK) 
$ 2 
(Plate 10, figs. 165-166; plate 31, fig. 222.) (131 aan f 
Leneth of body up to 24 mm.; antennae up to 15 mm.; cerei 
up to 18 mm. 
The nymphs of this species are strikingly marked with brown 
and yellow. 
Head a little narrower than the pronotum; transversely banded 
with yellow and dark brown. Entire occiput behind the epicranial 
suture yellow, except for a small area behind the compound eyes; 
area in front of the epicranial suture up to the region of the 
fronto-clypeal suture dark brown, except for the transverse M- 
mark and a small yellowish mark on the outside of the posterior 
ocelli. Clypeus yellow ; labrum dark brown; hind ocelli about twice 
as close to each other as to the eyes. Antennae yellowish, of about 
one hundred and five segments. 
Pronotum nearly twice as wide as long, slightly widened pos- 
teriorly, front margin somewhat convex, hind margin nearly 
straight; all angles broadly rounded. 
Legs much flattened; coxa, trochanter, and the basal part of 
