l'LECOPTERA OF NORTH AMERICA 95 



Distribution. — Type, male, June 4, 1911, Fairfax Co., 

 Va. (Banks Coll. Mus. Comp. Zool., Cambridge, Mass.) ; 

 three males, one female, June, 1912, Black Mts., N. C. 

 (Beutenmuller) ; one female, July, 1903, Newfoundland, 

 N.J. 



Perla bilobata, new species. 



(Plate 18, figs. 1, 2, 3; plate 14, fig. 7.) 



Length to tip of wings, male, 10-12 mm. ; female, 12-14 

 mm. Expanse, male, 18-21 mm. ; female, 21-24 mm. 



General color brown with a median, yellow prothoracic 

 stripe and with the wings lightly to heavily infuscated. 

 Head a little wider than prothorax, yellowish brown with 

 a darker mark over the ocellar triangle and with a dark 

 spot on the clypeus ; frontal ridge and lateral tubercles not 

 prominent ; ocelli small, hind ocelli closer to the eyes than 

 to each other. Antennae yellowish brown. 



Prothorax yellowish to chocolate brown, with a yellow 

 median stripe ; wider than long ; slightly narrowed behind ; 

 angles rounded (in pinned specimens almost sharp) ; sur- 

 face only slightly rugose. Legs yellowish brown, a nar- 

 row black transverse band at end of femora; first and 

 second tarsal segments short, subequal; third segment 

 long. Wings lightly to heavily infuscated ; subcosta ends 

 considerably before the cord ; a series of costal crossveins 

 before the end of subcosta and several beyond ; radial sec- 

 tor usually with three branches. 



Abdomen and tails yellow. 



Male. Seventh and eighth abdominal sternites each 

 with a median, rounded, knoblike appendage, the larger 

 one on the seventh sternite ; ninth sternite somewhat 

 triangularly produced ; ninth tergite slightly emarginate 

 behind and spinulose each sfde of the median line ; tenth 

 tergite cleft and each side with a rounded, raised lobe 

 closely beset with short pegs ; supra-anal process normally 

 retracted ; when extended it consists of a basal, mem- 

 branous sheath and a central, slender, chitinous recurved 

 process which bears at the tip a long, slender, lash-like 

 filament ; subanal lobes broadly triangular, unmodified. 



Female. Hind margin of eighth abdominal sternite 

 produced into a broad, evenly rounded subgenital plate 

 which normally does not extend entirely across the ninth 

 sternite. 



Holotype male, allotype female, July 19, 1905, Old 

 Forge, N. Y. (J. G. Needham) ; Paratypes, many speci- 

 mens, males and females, July 16-19, 1905, Old Forge, 

 N. Y. (J. G. Needham) ; three males, two females, June- 

 Aug., Black Mts., N. C. (Beutenmuller). 



