126' THOMAS SAY FOUNDATION 



N. Y., June 17; Alcohol Brook, Adirondack Lodge, N. Y., 

 July 1, 1923 ; Mt. Desert, Me., June 10, 1921 (C. W. John- 

 son). 



Alloperla nanina Banks. 



(Plate 20, figs. 3, 4.) 

 ]9J1. Alloperla nm ina Hanks, Trans. Amer. Ent. Soc, 37:366. 



Length to tip of wings, male, 7.5-9.5 mm. ; expanse, 

 male, 13-16 mm.; length to tip of wings, female, 9-11 

 mm. ; expanse, female, 15-19 mm. 



General color pale yellow with greenish wings. 



Head a little wider than prothorax, yellow or greenish ; 

 hind ocelli closer to the eyes than to each other; antennae 

 yellow at base, darker toward the tip. 



Prothorax transversely oval, wider than long; yellow 

 with the median portion sometimes a little darker; sur- 

 face very slightly rugose. Legs yellowish, tarsi darker 

 towards the tip. Wings greenish hyaline ; veins green- 

 ish yellow. 



Abdomen pale greenish, without a dark dorsal stripe. 

 Cerci yellowish, a little darker towards the tip. 



Male. Tenth abdominal tergite cleft; ninth tergite 

 pushed forward so as to appear deeply emarginate be- 

 hind; supra-anal process recurved, flattened dorso-ven- 

 trally, the apical margin serrate or closely beset with 

 spines and at the tip and above just before the tip with 

 a bunch of hairs; subanal lobes small, unmodified; ninth 

 sternite produced and somewhat truncate behind. 



Female. Hind margin of eighth abdominal sternite 

 centrally produced into a narrow tongue-like sub-genital 

 plate, which normally reaches entirely across the ninth 

 sternite. 



Distribution. — Type, female, No. 11343, May, Black 

 Mts., N. C. (Banks Collection, Mus. Comp. Zool., Cam- 

 bridge, Mass.) ; paratypes, two males, four females, May, 

 Black Mts., N. C. (Banks Coll.). Many males and fe- 

 males, May, June and July, Ithaca, N. Y. ; one male, July 

 5, 1923, Oxford, N. Y. ; males and females, July 1-2, 1923, 

 West Branch, Ausable River, Essex Co., N. Y. ; two males, 

 two females, July 2, 1923, Elizabethtown, N. Y. ; one male, 

 one female, July 1, 1923, Adirondack Lodge, N. Y. ; one 

 male, May 18-26, 1911, Clayton, Ga. (J. C. Bradley) ; 

 many males and females, June 13-26, 1913, Truro, N. S. 

 (R. Matheson). 



There seems to be some variation in the structure of 

 the small chitinized tip of the supra-anal process of the 

 male. In some of the males the tip is rounded and 



