148 THE CANADIAN ENTOMOLOGIST. 



anterior and middle tibice with a black spot behind, but Jiind tibice 

 wholly yellow. Closely related to C. andrenifonnis, Smith, but much 

 larger, with a much broader face, and the femora mainly black. It is also 

 very much larger and broader-faced than C rhodophilus, Ckll. 



Boulder, Colorado, at flowers of Grindelia perennis, Nelson, August 

 ( S. A. RoJnver). 



Cresson's description of the male of this species is very short, but I 

 think there is no doubt about the identity of our insect. There is in this 

 group a curious sexual difference in the first abdominal segment, which is 

 much more closely and minutely punctured in the males than in the 

 females. 



C. dilorops, Ckll., was based on a male of this group, easily dis- 

 tinguished from coloradensis by the colour of the legs and the smaller size. 

 C. coloratipes (Ckll.) is very like chlo?'Ops, hwi the eyes in both sexes have 

 a sort of purple colour, instead of the characteristic green of chlorops and 

 colorade?isis. The species common at Phcenix, Arizona, at flowers of 

 Compositae {Heieroiheca, etc.) hitherto regarded as coloratipes, has green 

 eyes, and must be associated with chlorops, though, perhaps, racially 

 separable. A male from Florissant, Colorado, at first referred to 

 coloradensis, proves to be chlorops. Two females from Soledad Canon, 

 Organ Mts., New Mexico, (C. H. T. Townsefid), belong to chlorops, 

 resembling the Arizona form. The females of coloratipes, and also those 

 of the Arizona form of chlorops (in each case taken in copula with the 

 males), have the light dog-ear marks on the face, which are wanting in 

 coloradensis $ . The more northern and typical chlorops, however, seems 

 to have a female without these marks ; and at present I do not know how 

 to separate this from coloradensis. There is just a possibility, perhaps, 

 that coloradensis was founded on females of chlorops and males of the 

 Boulder species described above. 



A female which I collected at Rinconada, New Mexico, at a tall 

 species of Chrysothajnjws, Sept. 26, represents an intrusion of the 

 southern type into northern New Mexico, up the Rio Grande Valley. It 

 has the dog-ear marks very well developed ; and the lateral marks are 

 peculiar, being broad and obliquely truncate above, with a linear upward 

 extension quite distinct from the truncation. This may represent a 

 distinct local race. 



