ODYNERUS. 275 



the antennae and flagellum beneath rather ferruginous ; macula; 

 behind the eyes, orange. Thorax shorter, more cubical. Pro- 

 thorax rufous margined with yellow anteriorly. Post-scutel and 

 angles of metathorax yellow. First abdominal segment rufous 

 above, surrounded with yellow; the mandible often black. Second 

 segment having its marginal impressed band much impressed and 

 broad; segments 1-5 margined with yellow. Coxae and feet 

 adorned with yellow (Louisiana). 



Texan Variety. — Prothorax, scutels, metathorax, feet, segments 

 1, 2 of the abdomen, rufous. Disk of mesothorax rufous on each 

 side. Border of prothorax, a dot under the wing, two spots on 

 the tegulae, scutel, post-scutel, edges of segments 1-6, bright 

 yellow ; the first segment having on each side a yellow spot 

 smelted with the marginal fascia (Texas). 



Mexican Variety ?.— Smaller. Length, 13 mm. ; wing, 10.5 mm. 



9. Black; mandibles, scape of the antennas, forehead and the 

 parts behind the eyes, prothorax, a lateral spot, tegulae, two 

 maculae on disk of mesothorax, scutel, feet, and coxae, rufous. 

 Post-scutel yellow. Angles of metathorax rufous and yellow ; 

 abdomen rufous ; first and second segment with a black portion 

 in the middle and at base; all the segments margined with 

 yellow; the first band fused on each side with a lateral square 

 yellow spot, and the 2d segment having on each side a yellow 

 spot, either free tfr confounded with the margin. Anus yellow. 

 Wings washed with fuscous, with a golden, rather violet reflec- 

 tion; the radius ferruginous. The metathorax, although forming 

 two lateral angles, is not toothed; the superior part of its poste- 

 rior face is not margined on each side by an oblique ridge. 



Var. Of course the ferruginous varies into yellow and vice 

 versa, and the black is more or less developed. 



Bess. a. dif. This species resembles 0. arvensis, but it is 



more slender 2; the male has also a more transverse, very regular 

 polygonal clypeus, while in arvensis it is more prolonged at its 

 extremity ; in the female, the clypeus is on the contrary narrower 

 than in arvensis. The post-scutel is not as strongly but quite 

 delicately crenulate. The metathorax is not so sharp, and it has 

 altogether another appearance. It approaches quite closely to 

 pratensis, has the same look, but differs: by its 2d abd. segment 

 not smooth, but densely and strongly punctured throughout; by 



