110 THOMAS SAY FOUNDATION 



Alloperla marginata Banks. 



( Plate 22, figs. 10, 11.) 

 1897. Chloroperla marginata Banks, Trans. Am. Ent. Soc, 24:21. 

 1907. Alloperla marginata Banks, Cat. Neur., p. 13. 



Length to tip of wings, male, 8 mm. ; expanse, male, 

 14 mm. ; length to tip of wings, female, 9-10 mm. ; ex- 

 panse, female, 16-18 mm. 



General color pale yellowish with the lateral margins 

 of prothorax usually blackish. 



Head hardly wider than prothorax, pale yellow ; ocelli 

 black; hind ocelli closer to eyes than to each other; an- 

 tennae yellowish at base, somewhat infuscated towards 

 the tip; palpi yellow, last segment of maxillary palpi 

 small. 



Prothorax about as wide as head, transversely oval, 

 wider than long, yellow ; lateral margins usually with 

 a narrow dark line ; surface somewhat rugose. Legs 

 yellow, tarsi darker. Wings hyaline with a yellowish 

 green tinge, veins yellowish ; subcosta reaches to a point 

 somewhat beyond the middle of the origin of the radial 

 sector and the cord. 



Abdomen yellow with a broad blackish median dorsal 

 stripe over at least the first seven segments. Cerci yel- 

 low, closely beset with long hairs. 



Male. Supra-anal process represented by a short, broad 

 membranous lobe which bears at the tip a small round 

 knob which is thickly clothed with hair; subanal lobes 

 small triangular, unmodified ; at the base of each cercus 

 the tenth tergite bears an inward pointing slender proc- 

 ess; ninth abdominal sternite produced and somewhat 

 truncate behind. 



Female. Subgenital plate of eighth abdominal sternite 

 as broad as the eighth segment and greatly produced into 

 an evenly rounded plate which in dried specimens reaches 

 to the tip of the abdomen. 



Distribution.— -Type, female No. 11348, July 6, 1895, 

 Colden, N. Y. (Banks Coll. Mus. Comp. Zool., Cambridge, 

 Mass.). 



Four males, five females, Aug., Mt. Katahdin, Me. ; one 

 female, June 20, 1922, Moore's Brook, Ithaca, N. Y. (C. K. 

 Sibley) ; one female, Milw. Co., Wis. (F. R.) ; one male, 

 Mt. Greylock, Mass. 



