118 HYMENOPTERA. 



PROSOPIS GROSSICORNIS Swk. and Ckll. 1910. 

 1910. P. grossicornis, Swk. and Ckll. Ent. News. 21 : 67. 



J/a/^'.— Distinguished by its small size, impunctate abdomen, faintly 

 punctured head and thorax, and face marks resembling those of P. 

 trident uliis. Small, about 4^ mm., resembling P. cressoni in size, form 

 and puncturation. 



Sculpture.— Yery sparse and light on head and thorax, resembling in 

 this respect, forms of P. cressotn ; enclosure of propodeum often smooth. 



Yellow Markings. — Face marks almost identical with those of P. 

 tridentulus, except in size, and as follows : Supraclypeal mark seldom 

 extending above antennal sockets ; clypeus always broad at base ; 

 scape normally with a yellow stripe in front ; and labrum and mandi- 

 bles dark. Thorax without markings. Legs with most of tibiae and 

 tarsi yellow, except median third of middle and hind tibiae. 



Genitalia. — Armature almost identical with that of P. cressoni, and 

 P. rudebeckia , not at all like that of P. tridentulus. Ventral plates 

 very similar to those of P. tridentulus , except in size, and in the distal 

 pedicel of eighth being shorter, (figs. 19, 42, 48). 



Female. — Unknown or indistinguishable. 



Habitat. — Not well known. Specimens at hand are from 

 Neb., Wise, Alab. and Cana. Type locality Lincoln, Neb., 

 May 14, 1901. Taken on flowers of Tamarix gallica (L. 

 Bruner). 



Specimens examined : Type, loaned by Swenk, and six 

 specimens in the Baker collection. The description is based 

 upon the type, except for the genitalia, which are from the 

 others. 



This little species is very interesting in being related to 

 P. cressoni so closely in size, form, puncturation, and genital 

 armature, and to P. trident^ihis in markings and ventral plates. 

 The seven specimens are practically identical in sculpture 

 and markings, and the genitalia show no variation whatever. 

 Only one specimen shows much variation in marks ; this 

 lacks the yellow on scape, and has less clearly cut face 

 marks, (fig. 84) and (fig. 87). 



It is not improbable that the insect described by Cockerell 

 as P. digitata fedorica, (1909 Ann. and Mag. Nat. Hist. Ser. 

 VIII, 4:27) belongs to this species, as the description 

 would indicate ; in which case the name would have to be 

 changed to P. fedorica Ckll., but not having any authentic 

 specimens of the latter I am not prepared to make the 

 change. 



