CHARLES W. HOOKER. 77 



Wings hyaline, occasionally tinged with fulvous, stigma and costa 

 flavous, nervures tinged with fuscous; marginal nervure (costa) slightly 

 thickened and sinuate near the small stigma, discocubital vein weakly 

 sinuate, its bulla one-half the width of the third discoidal cell from its 

 apex ; discocubital cell with two maculae in the glabrous area, the 

 larger subtriangular, with a chitinous, usually yellowish, continuation 

 along the hinder margin of the glabrous area to a point beyond the 

 smaller macula, which is anterior and lateral to the center of this area ; 

 the smaller subtriangular to crescentic ; nervulus antefurcal to inter- 

 stitial, nervellus broken far below the middle, first recurrent vein 

 about one-half the length of the second. Legs flavous, claws pectinate. 



Abdomen flavo-fuscous, strongly compressed and varied with fusc- 

 ous or black along the venter and at the apex, the two basal segments 

 slender ; claspers of male rounded apically. 



In redescribing this species I have examined two 9 co- 

 types, twelve 9 and one cf specimens. 



Cotypes. — Three 9 's, New York State Museum, Albany ; 

 9 , Cornell University, Ithaca ; 9 , Massachusetts Agricul- 

 tural College. Paratype, U. S. National Museum. 



This is a comparatively rare subspecies often confused 

 with E. purgatus Say, since it is probably found throughout 

 the range of the latter ; it is, however, usually larger and 

 lighter colored than E. purgatus, while the larger macula is 

 appendiculate and the bulla of the discocubital vein distant 

 one-half the width of the third discoidal cell from its apex ; 

 in purgatus the larger macula is usually not appendiculate 

 and the bulla of the discocubital vein is distant only one- 

 fourth of the width of the third discoidal cell from its apex. 

 However, these differences are not constant, but appear in 

 different degrees and combinations in both, and I do not see 

 how arcuatus can be considered more than a subspecies. 

 The fact that the distributions of the two coincide favors this 

 view. 



Dist7'ibution. — The range of this species probably coincides 

 with that of E. purgatus Say, although data available at present 

 show a somewhat more limited distribution. The present 

 known range extends from Durham, N. H., to Illinois, and 

 south to Florida and Mexico. It has been reported from Illi- 

 nois and Georgia, and I have seen specimens from New 

 Hampshire, Massachusetts, Connecticut, Rhode Island, New 



TRANS. AM. KNT. SOC. , XXXVIII. 



