REVISION OF THE GEIJ^US EXETASTES — CUSHMAN 309 



Natural History, Boston Society of Natural History, Cornell Univer- 

 sity, California Academy of Sciences, and the collections of H. K. 

 Townes and A. R. Park, Jr. 



It is on the wing late in July and in August and, especially in the 

 southern part of its range, as late as the middle of September. 



Despite its abundance, only one rearing record is available ; a male 

 was reared in September 1892 from a larva of Cucullia asteroides 

 Guenee at Canobie Lake, N. H., by George Dimmock. 



55. EXETASTES NERVULUS (Say) 



The first to recognize this species as an Exetastes were Cushman and 

 Gahan.^ The spechnens then identified by them as nervulus are here 

 treated as a new variety. 



Structurally similar to suaveolens, but with the ocelli slightly smaller, 

 the notauU virtually effaced, and the legs, notably the hind femur, 

 somewhat stouter. Distinguishable also by the black hind tibia and 

 the entire absence of black on the front and middle femora. 



Except for the slightly larger size of the typical nervulus, I have 

 been unable to find any structural characters to distinguish from it 

 niger Cresson, nifofemoratus Provancher, and exploratus Davis. 

 However, the differences in the color of the hind femora and tarsi are 

 too sharp to be ignored, even though bridged by the new variety 

 intermedius and by variation within the varietal limits, and I recog- 

 nize them as color varieties. 



The black hind femur of the typical form is approached in the 

 new variety, and the dark wings in niger and exploratus; in riifqfemor- 

 atus the hind femur is sometimes considerably infuscate at apex and 

 on the other side this variety sometimes approaches exploratus in the 

 color of the hind basitarsus; while exploratus is intermediate in tarsal 

 color between rufofemoratus and niger, the apical tarsal joints in the 

 last named being sometimes yellowish. 



The varieties nervulus, intermedius, and rujojemoratus are north- 

 eastern in distribution, while exploratus represents the westward 

 extension of the species and niger the southwestern extension, the 

 species through its varieties ranging from Nova Scotia to British 

 Columbia and New Mexico and the typical form as far south as North 

 Carolina. 



The varieties may be distinguished by the following key: 



KEY TO VARIETIES OF EXETASTES NERVULUS (SAY) 



1. Hind femur black or uniformly more or less deeply piceous 2 



Hind femur ferruginous, sometimes more or less infuscate at apex 3 



2. Wings deeply infumate; hind femur black; 15 mm nervulus (Say) 



Wings dilutely infumate; hind femur piceous; less than 15 mm. 



intermedius, new variety 



' Proc. Ent. Soc. Washington, vol. 23, p. 159, 1921. 



