THE CANADIAN ENTOMOLOGIST. 21?, 



SYNOPSIS OF PROSOPIS AND COLLETES, WITH SUPPLE- 

 MENTARY NOTES AND DESCRIPTIONS. 



BY CHARLES ROBERTSON, CARLINVILLE, ILLINOIS. 



This paper belongs with the series on local species — Andreninne, 

 Megachilidse and Bombinai, Tr. Am. Ent. Soc, 2S: 187; 2g: 163; Spheco- 

 dinte, Ent. News, 14: 103; Balictinae, Nomadinte, Epeolinse, Anthophila, 

 Can. Ent., 34 : 245 ; jj : 172, 284 ■,36: 37. 



For the length of the malar space is taken the shortest distance 

 between the eye and the mandible : the breadth is that of the mandible at 

 base; joint refers to antenna, segment to abdomen; cells III5 and III^ are 

 the second and third submarginal cells. 



Of 81 specimens formerly referred to P. modesta. Say, 45 are referred 

 to P. Iili?ioiensis, and 36 to P. Sayi, sp. nov. I have given up the 

 attempt to identify P. modesta. Say. The type of P. Sayi is a pair taken 

 in copula on flowers of Heracleum lanatum, June 4, 1888. Both have a 

 dot on tegula. 



According to my separation of them, P. Illinoiensis sometimes has a 

 dot on tegula, and P. Sayi often has. The determination of P. affinis 

 thus becomes more doubtful than ever. I use the name P. zizice for the 

 insect I have always called P. affinis^ Sm. 



Prosopis, Fabricius. 



Females 



Front coxa with a lateral tooth : eyes short ; cheeks broad ; face 



marks, tubercles, sometimes two lines on collar, front and middle 



knees, and base of hind tibiae, yellow ; enclosure of metathorax rugose 



on basal middle ; 6 mm thaspii. 



Front coxa simple ; eyes long ; cheeks narrow ; at least bases of tibise 

 yellowish ; metathorax usually more rugose i. 



1. Segment i and base of 2 red; face marks, tubercles, and dot on tegulae, 



yellow ; wings beyond middle clouded ; 6-7 mm nelumbonis. 



Segments 1-6 black 2. 



2. Collar with yellow marks; tubercles and face marks yellow; 5-6 mm. 4. 

 Collar black ; 4-5 mm 3. 



3. Entirely black, except bases of tibise and sometimes narrow lines on 



face; slender saniculae. 



Clavate face marks present ; usually a spot on clypeus, tubercles and 

 tegulse ; a little more robust pygmrea. 



