CRABROXID^. 



159 



Cresson remarks that Eucerceris (Fig. 86, fore wing of male ; 

 0, female) ditiers from Cerceris in the venation, which differs 

 greatly in the two sexes. E. zonatus Say 

 occurs in tlie west. 



The species of Cerceris (Fig. 87, wing) 

 have transversely oblong heads, the front of 

 the head is flattened and destitute of hairs, 

 and the rings of the abdomen are contracted, 

 the middle part being un- 

 usually convex and coarsely 

 punctured, while the basal 

 ring is nearly one-half nar- 

 rower than the succeeding 

 ones. Cerceris deserta Say is our most com- 

 mon form. In lilurope some species are Fig. 87. 

 known to store their nests with bees, and the larvie of Cur- 

 oilionidce and Buprestidce . Dufour unearthed in a sin- 

 gle field thirty nests of C. bupresticida which were filled with 

 ten species of Buprestis, comprising four hundred individuals, 

 and none of any other genus. Cerceris tuberculafa provisions 

 its nest with Leucosomus ophthalmicus ; and C. tricincta with 

 Clythra. 



In the subfamily Crahronina\ there is a great disparity in 

 the sexes, the form of the females being the most persistent. 

 In the male the head is smaller, narrow behind, with shorter 

 mandibles, and a narrower clypeus ; the body is also much 

 slenderer, especially the abdomen, and the legs are simple in 

 Crabro, but in Thyreopus variousl}^ modified b}- expansions of 

 the joints, especially the tibia. The 

 species of Crctbro (Fig. 88) are readily 

 distinguished by the large cubical 

 head, and the sharp mucronate abdo- 

 minal tip of the female. The more 

 typical form of this \ery extensive 

 genus is Crabro sex-macHlatus Say, 

 so-called from the six yellow spots 

 on the subpedunculate abdomen. According to Dr. T. "W. 

 Harris (MS. notes), this wasp was seen by Rev. ]\Ir. Leonaid. 

 of Dublin, N. H., burrowing in decayed wood, June 10th. 



