26 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 82 



PSEN (MIMUMESA) MODESTUS RETICULATUS, new variety 



Plate 1, Figure 12 



Male. — Differs from the above in having the antennae brownish 

 yellow below on almost the entire flagellum, and the propodeum with 

 almost the entire surface rugoso-reticiilate (pi. 1, fig. 12). 



Type.—V.S.l^M. No. 44231, from Caroni River, Trinidad, October 

 12, 1916, A. 757 (H. Morrison). 



PSEN (MIMUMESA) COLORADOENSIS Cameron 



Pscyi coloradodvsis Camesron, Trans. Amer. Ent. Soc, vol. 34, p. 232, 1908. 

 (Female.) 



It appears to me certain that this species, the exact identity of 

 which I am unable to arrive at, belongs to this subgenus, as the 

 describer stated that it would fall in Fox's group 2, and runs near 

 cylindricus and regulans. 



Judging from the description, it falls in the same group with niger, 

 mixfus, and leucopus, with a possibility that it may be the second 

 species. 



Locality. — Berkeley County, Colo. (= Berkeley, Calif.?). 



PSEN (MIMUMESA) INTERSTITIALIS Cameron 



Psen interstitialis Cameron, Trans. Amer. Ent. Soc, vol. 34, p. 233, 1908. 

 (Male.) 



Cameron rejected the idea that this might be the male of colorado- 

 ensis owing to the interstitial second recurrent and cubital nerves, 

 the lack of a distinct frontal keel, and the shorter abdominal petiole. 



As there is a great deal of variation in the positions of the cubital 

 and the recurrent nervures, I am not inclined to consider the char- 

 acter of importance in the distinction of species. The lack of a 

 frontal keel would appear to suggest that the species does not belong 

 to this subgenus, but the observation may not have been accurate, 

 and there is some variation in the length of the abdominal petiole 

 in many species of the subfamily, especially in the sexes of certain 

 species. It is impossible to decide what this species really is without 

 examination of the type. 



Locality. — New Mexico, no definite location. 



The types of both the above species were in the Cameron collection, 

 which is, I believe, in the British Museum of Natural History in 

 London. 



Subgenus Mimesa Shuckard 



Reference as under genus, p. 6. 



The two characters which can be depended upon invariably for the 

 separation of members of this subgenus from the Miinumesa are the 



