162 THOMAS SAY FOUNDATION 



long as one and two combined. Wings subhyaline to dark 

 fumose; base of costa, subcosta and radius usually yel- 

 low; no costal crossveins before the end of subcosta 

 (rarely one or two faint crossveins) and one to four costal 

 crossveins beyond the end of subcosta; subcosta ends just 

 before the cord; radial sector with two branches; fore- 

 wing with one to three crossveins between first and sec- 

 ond anal veins ; hind wing with a large anal field ; two tc 

 four cubital crossveins. 



Abdomen brown, lighter underneath, in the male the 

 ninth sternite is yellowish. Cerci with the first 6-8 seg- 

 ments usually yellowish, beyond the segments are tipped 

 with brown, becoming entirely brown at the tip; middle 

 segments 4-5 times as long as wide. 



Male. Ninth abdominal sternite much produced and 

 bearing near the end a yellow, transversely rounded knob, 

 the area each side of the knob being deeply excavated; 

 tenth abdominal segment entire, normally retracted with- 

 in nine; subanal lobes modified into slender, sharply 

 pointed, finger-like processes which recurve upon the 

 tenth tergite ; supra-anal process not developed. 



Female. Hind margin of eighth abdominal sternite 

 slightly produced into a bilobed subgenital plate, some- 

 what truncate behind and medially with a squarish notch ; 

 ninth sternite each side with a dark mark. (In some fe- 

 males the lobes of the subgenital plate, each side of the 

 median notch, are more produced and square at the tip.) 



Distribution. — June 9-July 19, Ithaca, N. Y. ; July 31, 

 1922, Canandaigua Lake, Naples, N. Y. (M. D. Leonard) ; 

 one male, June 16, Pa.; male and female, May 26, Hot 

 Springs, Ark. ; one male, N. C. ; one female, April 17, 1903, 

 Raleigh, N. C. (C. S. Brimley) ; one male, June 10, N. 

 Reading, Mass. (C. W. Johnson) . 



Genus PERLINELLA Banks. 



1900. Perlinella Banks, Trans. Amer. Ent. Soc, 26:242. 

 1907. Perlmella l J >;mks, Cat. Neurop., p. 12. 

 1909. Perlinella Enderlein, Zool. Anz., 34:389. 



Medium sized stoneflies 10-19 mm. in length; brown, 

 with two broad yellow stripes on pronotum and with a 

 row of crossveins in anal field of forewings. 



Head a little wider than prothorax; yellow with two 

 large black spots, one covering the ocellar triangle and ex- 

 tending outward toward the base of the antennae and the 

 other over the clypeus in front of the yellow frontal ridge ; 

 three ocelli, the hind ocelli about as close to each other 

 as to the eyes. Antennae blackish. 



