CHARLES W, METZ. 139 



variation, but not enough material has been obtained to ascer- 

 tain this with certainty. In both sexes the posterior face of 

 the propodeum is cut squarely off as if with a knife, making 

 a sharp angle above and on sides. 



PROSOPIS MEGALOTIS Swk. and Ckll. 1910. 

 1910. P. niegaloiis, (male and female) Swk. and Ckll. Ent. News. 

 21:69. 



This species is very nearly related to P. asinimcs Ckll. the 

 description of which will apply here except in a few particu- 

 lars. In the male the external difference is mainly in the 

 larger size, broader face, with heavier, more truncate lateral 

 marks : and in the large amount of yellow on the labrum and 

 mandibles as shown, (fig. 108). The ventral plates of the 

 male, are considerably different from those of asininns, how- 

 ever, being like those of colorade7isis and polifolii in lacking 

 the peculiar ear-like flaps. The females of the two species 

 differ in merely secondary characters ; the lateral face marks 

 being shorter and the yellow on collar being broken in the 

 center. In both sexes the mesoscutum is more densely punc- 

 tured, with smaller punctures than in asinitms, and the pro- 

 podeum lacks the sharp angle above : the surface being 

 rounded instead of cut off abruptly, (figs. 108, 119). 



Habitat. — Nebraska; Colorado; types of both sexes from 

 "Glen, Sioux Co., Neb. Aug. 17, 1906; on Cleome serrulata 

 (M. H. Swenk)". In coll. Univ. Neb. 



Mr. Swenk records fifty specimens, all but one from Ne- 

 braska. Found on Cleome and Solidago. in August. 



This species is a very near relative of P. asininns and may 

 prove to be a variety of that when more material is obtained. 

 Two paratypes from Mr. Swenk have been examined, which 

 differ from asiniyiiis as shown above; in them the distinguish- 

 ing characters are quite plain, but what will be found in an 

 adequate series cannot be foretold. 



PROSOPIS COOKII n. sp 



Male. — Ver>' small ; related to P. asininns Ckll. but much smaller, 

 with face broader above, lateral marks shorter, and very diflferent 

 genitalia. 



Length 3\-'^ mm. Slender; posterior face of propodeum cut off 



TRANS. AM. ENT. SOC. , XXXVII. 



