42 U.S. NATIONAL MUSEUM BULLETIN 2 89 



extreme wing base in others (including generotype) ; marginal fringe 

 relatively elongate, equaling width of forewing in some species. 



Male genitalia. — Uncus reduced typically to a small conical lobe, 

 fused to tegumen. Tegumen relatively narrow. Gnathos absent. 

 Transtilla usually well developed, often arched at middle. Valvae 

 short, stout, outer half either entire or deeply divided into 2-4 lobes 

 of various sizes. Aedeagus either elongate and slender or more short- 

 ened and clavate; cornuti usually numerous and arranged in dense 

 patches, sometimes few in number and scattered; ejaculatory duct 

 usually entering above middle. Spermatophore elongate, slender, ap- 

 proximately same diameter throughout; aperature either at middle 

 or at apical end. 



Female genitalia. — Ovipositor moderate to long; posterior apo- 

 physis usually about 1.5 X length of anterior pair. Sinus vaginalis 

 broad; caudal portion of ductus bursae frequently expanded into a 

 thick walled antrum; remainder of ductus bursae slender, gradually 

 enlarging to form long, narrow corpus bursae; signa absent. 



Discussion. — The systematic treatment of this genus, like that of 

 Carposina, still leaves much to be desired. After an adequate study of 

 all the specjes has been completed, it may be decided that the 

 Australian specjes and the two more or less distinct groups of North 

 American species require separate generic or subgeneric placements. 

 As now envisaged, no single set of characters clearly defines the 

 group, although a combination of several features loosely associates 

 the known species. The male and female genitalia of the American 

 forms are rather similar to those of the Australian in general mor- 

 phology and provide the best set of characters for delimiting the 

 group. Although the females of the generotype, B. nigella, possess 

 similar genitalia, the morphology of the male genitalia diverges 

 particularly in the structure of the valvae. In B. nigella the cucullus 

 is simple and entire with a short but stout ampulla arising from the 

 apex of the sacculus. In addition, this species differs from all the 

 American forms, with the exception of B. comonana, in possessing 

 strongly dimorphic labial palpi. The female palpi in the North 

 American species gradually progress from the type observed in 

 B. jidelis, in which the females are superficially identical to the 

 males, through intermediate forms such as B. crescentella, to the 

 extreme type possessed by B. comonana. The relative dimorphism 

 of the labial palpi, beside being gradual, also does not appear to be 

 correlated with any other characters as a possible criterion for sub- 

 dividing the genus. For example, in the case of another interspecifically 

 variable character studied, it was observed that some species with 

 reduced palpi in the female had veins 3 and 4 stalked in the hindwings, 

 whereas in others with similar palpi these veins were separate. 



