SOME AMERICAN GEOMETRID MOTHS CAPPS 117 



well before outer angle; 3 and 4 approximate at base; lb bifurcate 

 near base; fovea absent; male with a bar-like structure near base be- 

 tween cubitus and lb. Hind wind (fig. 1A) broad; transverse line, 

 if present, appearing as a continuation of the transverse posterior line 

 of the fore wing ; outer margin slightly or strongly produced at vein 

 4 (removal of scales often necessary to note this) ; veins 6 and 7 

 approximate from cell [except the genus Evita (fig. 2A) in which 

 they are stalked]. 



Male genitalia : Uncus simple, strong, hooklike ; socii short or rudi- 

 mentary ; gnathos well developed with numerous spines ; harpe simple ; 

 lateral arms of anellus strongly sclerotized, extending almost to costa 

 of harpe; furca simple, only the right branch developed (in ventral 

 view) ; aedeagus slender, cylindrical, narrowed posteriorly, distal end 

 with a rather strongly sclerotized extenuated platelike structure with 

 the margin serrate or scobinate. 



Female genitalia : Signum a strongly sclerotized plate, margin ser- 

 rate or spinose ; ductus bursae strongly sclerotized or with a narrow, 

 more or less complete internal sclerotized band posteriorly near junc- 

 tion with bursa copulatrix; ductus seminalis from near junction of 

 ductus bursae and the bursa. 



The variability in the shape of the wings and venation, particularly 

 the fore wing, prevents extensive use of such characters as the origin 

 of the veins, degree of anastomosis, stalking, or size and shape of 

 the areoles for separating genera of the Ennominae. Hence, as has 

 proved useful to other workers seeking a more natural classification 

 of difficult groups, the employment of genitalic structures for the 

 restriction of genera when other characters were unsatisfactory 

 appears to be adaptable to the development of a more desirable re- 

 arrangement of the species of this subfamily, and on this basis the 

 author has undertaken a study of the American Ennominae and is 

 preparing a revision of the group. 



KEY TO THE GENERA 



1. Hind wing with veins 6 and 7 stalked Evita, new genus 



Hind wing with veins 6 and 7 not stalked 2 



2. Fore wing with 3 transverse lines Besma, new genus 



Fore wing with 2 transverse lines 3 



3. Aedeagus of male with a rather strongly sclerotized bifurcate plate 



distoventrally ; ventral margin of genital opening of female bor- 

 dered by a narrow, strongly concave, sclerotized band ; central 



area of signum with spinules Neotherina Dognin 



Aedeagus of male without a sclerotized bifurcate plate distoven- 

 trally ; ventral margin of female genital opening not bordered 

 by a sclerotized band ; central area of signum without spinules 

 Lambdina, new genus 



