1 * s V cw I b: 
NFAV r.ENERA AND SPECIES OF PERLI1),E. 
liY NATHAN BANKS, WASHrNGTON, D. C. 
In going over my collection of stone-flies preliminary to a revision of the 
species, I found three new generic forms; one of them has just been described by 
Mr. Needham as Fcltoperla\ the two others are here described, as well as a few 
new species. 
Perla attenuata n. sp. 
Pale dull yellow; antenn.'E dark, paler on base; pronotum rather dull brownish; 
apical half of the abdomen brown; seta; brown, paler toward tip; wings hyaline, 
veins yellowish brown. Posterior ocelli rather closer to each other than to the 
eyes, and fully as far from the anterior ocellus; pronotum very broad, not much 
narrowed behind; anterior wings rather narrow, the discal cell is very slender 
and attenuate at base, the radial sector not bending out when arising from the 
radius as in other species, but running straight out or even curving forward a 
a little so that the discal cell is very narrow for a considerable distance; many 
median and cubital cross-veins; radial sector with four branches in one speci- 
men, three in another, beyond the cross-vein. The male genital area is concave, 
and between the bases of the setoe is seen a pair of small, shining hamules, or 
hooks, pointing forward. The ventral plate, which is rather broad, has an 
elevated transverse shining spot in the middle, and from each side of which a 
furrow extends outward and upward. Expanse 47 mm. Two specimens from 
Douglas Co., Kansas, June and July. 
Side. 
Top 
Perla Kansensis <? 
