352 Annals Entomological Society of America [Vol. IX, 



of front very faint ; vertex, occiput and cheeks punctured like the front ; 

 mesoscutum shining, densely punctured anteriorly, the punctures fine 

 and sparse on the posterior half; mesoscutellum finely and rather 

 closely punctured; episterna coarsely reticulate anteriorly, coarsely 

 obliquely rugose posteriorly; upper surface of propodeum coarsely 

 reticulate; posterior face of propodeum coarsely reticulate, with a large, 

 supra-medial, triangular fovea; sides of propodeum very coarsely 

 obliquely rugose; abdomen rather closely, microscopically punctate; 

 pygidium triangular, about one and one-half times as long as wide, 

 strongly punctured; wings hyaline; stigma and nervures of anterior 

 wings piceous. Entirely black. 

 cf . Unknown. 



Type: A female collected at Omaha, Nebraska, July 27, 

 1914 (L. T. Williams). Four paratypes as follows: Omaha, 

 June 20, 1914 (L. T. Williams), 1 9 ; Omaha, July 1, 1913 

 (L. T. Williams), 1 9 ; Omaha, August 29, 1914 (L. T. Williams), 

 1 9 ; one female specimen without data. 



Related to nigritiis, but differs in the differently sculptured 

 front and propodeum, and the mesoscutum not strongly 

 punctured before the mesoscutellum. 



Xylocelia cockerelli Rohwer. 



1909. Diodontus cockerelli Rohwer, Trans. Amer. Ent. Soc, xxxv. p. 105. 



Type locality: Florissant, Colorado. 



Xylocelia bidentatus Rohwer. 



1911. Diodontus bidentatus Rohwer, Proc. U. vS. Nat. Mus., xxxx, p. 560. 



Type locality: Nerepsis, New Brunswick. This species 

 cannot be the male of Xylocelia adamsi, as has been suggested 

 by Rohwer, because of the different structure of the clypeus. 



