116 CHARLES ROBERTSON. 



C'ollefos thoraoioa Sm. 



Tliis liiuidsoiue species, taken in Florida, maybe readily identified 

 from Smith's description. It was not recognized by Cresson. 



t'olletes willi»»touii Rob., Trans. Am. Ent. Soc. xviii, 60. 



Tile I closely resembles the $ . Thi.s is a little smaller than C. 

 latitarsi-^ Rob. and may be distinguished by the bind tarsi being much 

 more slender. 



C'ollotos ariuata Patton. Proc. Bost. Soc. Nat. Hist, xx, 143, 1879; C. seituli 

 Fattou. ibid.: C. inxqualis Cress, (nee Say), ibid, xii, 166, 1868; C. spinosit 

 Rob.. Trans. Am. Eut. Soc. xviii, 60, 1891. 



Cresson 's Catalogue does not give the synonyms of Patton 's paper, 

 for \vhich reason I did not know of them, and redescribed this species 

 and the next. All of the males which I have seen have some black 

 or fuscous hairs on the thorax above, which leads me to suspect that 

 the males referred to this species by Patton do not belong to it. I 

 have seen an example of the type of C. scitida and regard it as the 

 male of this Collete-i. 



Col lei es aestivalis Patton. Proc. Bost. Soc. Nat. Hist. xx. 142-4. 1S79: C. 

 heiicherse Rob., Trans. Am. Ent. Soc. xviii. 61, 1891. 



This species is the special pollinator of the flowers of Heuchera. 

 Mr. Patton captured it on flowers of Heuchera americana in Con- 

 necticut, and in Illinois I have taken it abundantly on H. hUpida. 



Colletes euloplii Rob.. Tiaus. .Km. Eut. Soc. xviii, 61 : Colletes Ul'inoiensis 

 Rob., ibid. ti-i. 

 This species closely resembles C. americana Cre.<s.. but ha.* the ab- 

 domen more .-trongly pimctured ami with narrower fa.scia?, and there 

 is a well-marked interval between the ba.-^e of the mandibles and the 

 eyes. In C. americana these almost touch, while in C eulophi there 

 is quite an interval, which in the % is subquadrate. 



Prosopis modestus Say : Hyhem modestun Say, Bost. Jour. i. 392, 1837. Lee 

 edit. ii. 771 : Proxopin affinin Sm., Brit. Mus. Cat. Hyni. i, 24, 1853 : Cress., 

 Proc. Bost. Soc. Xat. Hist. xii. 270. 



Prosopis pygnitea Cress. 



The 9 has the usual spots on the ba.<es of the tibia?, those on an- 

 terior pair extending nearly to tip. There is a variable yellow spot 

 on each side of face, one on tegulie, on tubercles, and often on apex 

 of clypeus, but .some specimens show no yellow markings, except on 

 the tibiie. I have taken the sexes in copula. 



