20 PROCEEDINGS OF THE NATIONAL MUSEUM vol.82 



1908 (P. R. Myers) ; Glen Echo, Md., August 10, 1923 (J. R. Mal- 

 loch) ; and one male, Takoma Park, Md. (C. N. Ainslie). 



PSEN (MIMUMESA) NIGER Packard 



Plate 1, Figure 9 

 Paen niger Packakd, Proc. Ent. Soc. Philadelphia, vol. 6, p. 399, 1867. 



This was selected by Fox as the species for which the group was 

 named, and I am using it as the subgenotype, having both sexes 

 available. 



The species is closely allied to the next two, from which it is dis- 

 tinguished by the characters cited in the key. 



Fox made use of the rather sparse and quite erect hairing of the 

 face and clypeus in distinguishing this species, mixttts, and leucopus 

 from their allies, but the character is not a very good one, though in 

 the females of niger at least it does occasionally strike one as rather 

 distinctive. The head behind the ocelli is very similarly punctured 

 in niger and leucopus, the principal distinguishing characters being 

 found in the enclosure of the propodeum. 



Length, 6.5-8 mm. 



Fox decided that Packard had confused the sexes of two species 

 under niger, and he retained as niger the species which he considered 

 " best befits the name." The localities cited by Fox are Virginia 

 and Canada, without more definite location. I have before me 

 examples from the following localities: Massachusetts (Baker collec- 

 tion) ; Long Island, N.Y., and Milwaukee, Wis. (Ashmead collec- 

 tion) ; Canada, without definite locality (Baker collection) ; Han- 

 over, N.H., and Sherbrook, Canada (Ashmead collection) ; and 

 Nerepis, New Brunswick, August 22 (A, G. Leavitt) ; Tallac Lake, 

 Tahoe, Calif. All are from the collection of the National Museum. 



PSEN (MIMUMESA) LEUCOPUS Say 



Psen leucopus Say, Boston Journ. Nat. Hist., vol. 1, p. 370, 1837. 

 Psen elongatus Packard, Proc. Ent. Soc. Philadelphia, vol. 6, p. 400, 1867. 

 (Male only.) 



Very similar to niger, distinguishable only as noted above and in 

 the key. 



Recorded from Virginia, Illinois, and New Hampshire. Before 

 me there are specimens from the following localities: Washington, 

 D.C., May 23 (C. L. Marlatt) ; Georgetown, D.C., no date (H. H. 

 Smith) ; Great Falls, Va., no date (H. H. Smith) ; and Glen Echo, 

 Md., May 26, 1923, and June 18, 1922 (J. R. Malloch). 



A female from Slave Lake, Alberta, Canada, taken on August 14, 

 1924, by Owen Bryant, has the tarsi darker than the specimen from 

 the United States but does not differ in any other material respect. 



