316 Trans. Acad. Sci. of St. Louis. 



ond segments depressed and somewhat reflexed, the margins 

 of following segments less reflexed, and becoming dull testa- 

 ceous; narrow fascia on first segment, becoming wider on 

 following ; beneath the segments have widely emarginato 

 margins with narrow rather dull fasciae. Length 8 mm. 



Illinois ; one ^ specimen. 



Easily distinguished by the short antennae having the third 

 joint longest. 



Sphecodes Latr. 



The males of this genus are often entirely black, or nearly 

 so, and in collections are likelv to be found mixed with males 

 of black species of Halictus, from which they are sometimes 

 hard to distinguish. From most males o{ Halictus they may be 

 separated by their shorter antennae. From those in which the 

 antennae of the males are short, like Halictus pectoralis, the 

 male Sphecodes may be distinguished by the flagellum being 

 submoniliform. As a rule the second submargiual cell is nar- 

 rower than in Halictus, and with its sides more parallel, less 

 narrowing towards marginal. 



Sphecodes dichrous Smith. 



Sphecodes dichroa Smith, Brit. Mus. Cat. Hym. I, 38, 9 (o^c ^), 1853. 



Sphecodes arvensis Patton, Am. Ent. Ill, 230, c^$, 1880. 



Halictus scabrosus Provancher, Nat. Can. XIII, 200, J*, 1882, Faun. Ent. 



Can., 700. 

 Sphecodes dichroa Provanclier, Nat. Can. XIII, 257, $, 1882, Faun. Ent. 



Can., 724. 



I have 19 5 and 18 ^ specimens, and have taken the sexes 

 in copula. Patton says that the female of S. arvensis differs 

 from that of S. dichroa in having the tip of the abdomen 

 black. He does not state, however, that he had identified 

 that species. The black at tip of the abdomen is sometimes 

 wanting, and, when present, is so variable in extent as to in- 

 dicate that its presence or absence is of little significance. 

 Provaucher's description of the female agrees with that of 

 Patton' s S. arvensis, while the male is redescribed as an 

 Halictus. The male is entirely black, with antennae rather 

 strongly moniliform, the fourth joint longer than the fifth, 

 and longer than the second and third together. The male 

 described by Smith evidently does not belong here. 



