HENRY J. FRANKLIN. 411 



the species, which Robertson placed in the genus Bombias, 

 fall naturally into two apparently distinct and widely dif- 

 ferent groups, as shown particularly by the differences in 

 the genitalia of the males. The differences between these 

 two groups (viz., Auricotnus and Fratermis) seem to strongly 

 indicate that they have had separate origins. Their geo- 

 graphical distributions, as far as they have been worked 

 out, seem to greatly strengthen this supposition. The dif- 

 ferences in structure, used by Robertson to separate Bom- 

 bias from Bombus, have evidently been independently evolved 

 by the two Bombias groups. In the opinion of the writer, 

 therefore, the name Bombias should be entirely suppressed, 

 as it seems to stand not for a natural, but for an artificial, 

 division of the old genus Bombus. However, as this division 

 is convenient, though artificial, and as the writer hesitates to 

 completely demolish a classification established by another 

 worker, until other investigators have expressed opinions 

 about the matter, Bombias has been reduced to a subgenus 

 and retained in this paper. The writer regards the Fraternus 

 group of the subgenus Bombias and the Dumoucheli group of 

 the subgenus Bombus as being very closely related and as 

 being the most primitive of all the groups of the genus Bovi- 

 bus present in the New World. 



Distinctive Characters of the Subgenus Bombias. 



Females with ocelli large and somewhat variable in position, 

 but typically below the supra-orbital line, in the narrowest 

 part of the front, the lateral ones farther from each other 

 than from the margins of the eyes (fig. D); lower side of 

 apical margin of mandibles usually protruding more strongly 

 than in the subgenus Bombus. The apices of the hind meta- 

 tarsi usually not drawn out into so prominent and acute a 

 projection, behind the insertion of the second tarsal segment, 

 as is the case in the subgenus Bombus {rufocinctus and mexi- 

 censis are two of the more notable exceptions to this). 



Males with eyes more or less swollen (fig. G) and bulging 

 out from sides of head ; ocelli large, usually placed well 

 below the supra-orbital line, the lateral ones usually not 



TRANS. AM. ENT. SOC. , XXXVIII. 



