24 G IIYMENOPTERA OF AMERICA. [PART I. 



Abdomen of little width; finely punctured, the first segment 

 long, almost as wide as the 2d, and boldly truncate on its ante- 

 rior face; the 2d cylindrical; its posterior border and the follow- 

 ing segments strongly punctured. 



Insect black, clothed with a short grayish pile. Mouth, 

 extremity and summit of the clypeus, a spot on the front, articles 

 1-5 of the antennae, red. Prothorax, wing scales, superior 

 angles of the clypeus and legs, equally red. First abdominal 

 segment above, wholly of a sombre-red; the second bordered with 

 red ; the border of 3d and often the anus slightly ferruginous. 

 Wings brownish, with violet reflections ; the side a little ferru- 

 ginous. 



Var. The 1st segment adorned with an orange border ; the 

 border of 2d passing also into orange. 



9. Clypeus pyriform, very coarsely cribrose, bicarinate toward 

 the base, prolonged and strongly truncate at the extremity ; its 

 little border biangulate but straight. 



% . Clypeus polygonal, a little longer than wide ; pale yellow, 

 covered with silvery hair ; its anterior border subconcave, sub- 

 bidentate. Antennae simple, terminated by a very small sharp 

 nipple. Inner border of the orbits yellow or ferruginous ; the 

 frontal spot yellow. Ridges of the metathorax still more tren- 

 chant, terminated superiorly by a more acute angle of a pyramidal 

 form. 



Var. Clypeus orange. 



Hess. a. diff. — This species, although similar in colors with 0. 

 Boscii and 0. arvensis, differs essentially from them by its 

 lengthened thorax, strongly retracted behind, by its little meta- 

 thorax, by its long metathoracic spines, its much more trenchant 

 and elevated ridges, its slender form, its clypeus longer than 

 wide, and the simple antennae of the males. 



The form of the abdomen slightly recalls that of the 0. l-sectus; 

 the livery that of 0. dorsalis, variety. 



Hob. The Southern United States. Carolina. Florida. 3 ? 

 1 % from Florida (E. Norton). 



