256 HYMENOPTERA OF AMERICA. [PART I. 



;ng varied with red or often almost entirely red. Legs yellow or 

 red, with the base of the thighs obscure. Wings of a brown- 

 reddish, slightly darkened, with some violet reflections (Carolina). 

 Far. a. Edges of metathorax a little blunted by the rugosities. 



b. Prothorax black, slightly bordered with red and very slen- 

 derly wi1 li yellow ; ornaments of the head red ; borders of the abdo- 

 men narrow. Clypeus black, with a yellow band on the summit. 



c. Clypeus black, with two yellow spots. 



d. Clypeus black, with two red points (New England). The 

 yellow and the red take each other's places and are more or less 

 developed. Base of legs black. 



e. Prothorax black, ornamented with yellow, without red. 



f. The 3d segment bordered with yellow. 



g. Insect distinctly black and yellow, without red. The orna- 

 ments of a sharp yellow. Clypeus black, with a yellow arcuate 

 band on the summit; a yellow line on the scape (New York, 

 Tennessee). 



h. Spots on the scutel very -small or none. 



%. Clypeus yellow, but little notched; post-scutel red or 

 yellow; first abdominal segment red, bordered with yellow. 

 Segments 3, 4 adorned with .a yellow edging. 



Bess. a. cliff'. — This Odynerus differs from the 0. dorsalis 9 

 by its wider clypeus, and by the trenchant and elevated ridges 

 which border the concavity of the metathorax above the spiniforni 

 angle, also by its smaller size, etc. From the 0. arvensis by 

 these same metathoracic ridges, which are more salient and 

 crenulate, which one may perceive especially in profile ; by its 

 black post-scutel and its scutel spotted with yellow; by its 3d 

 segment, a little less strongly punctured; its final segments not 

 bordered with yellow. Nevertheless these two species are allied. 

 — From the 0. Hidalgi by the absence of the reflexed border of 

 segments 2, 3, by the black post-scutel, the 1st segment not so 

 acutely truncate, etc. 



Bab. The United States, at the South. Florida, 1 9. South 

 Carolina, 2 9. Tennessee, 3 9. New York and Connecticut, 

 3 9 (E. Norton). 



The specimens coming from the South are especially marked 

 with red; those of the north become black and yellow. 



Observation. — Lepel de St. Fargeau has described a male, and 

 I unfortunately possess only females. He was evidently mis- 



