903 HYMENOPTEEA OF AMERICA. [PART I. 



Division PACHODYNERUS. 



Sauss. III e , Divis. Sect. I", Vespides, I, 169.— Divis. Epsilon, Sect. I, 

 ibid. III. 229, 252. 



Form relatively blunted (stubbed). Antennae of males simple, 

 not being terminated by a hook. Thorax short, inform of a 

 long or even cubical square, truncate posteriorly. The post- 

 scutellum transversely truncate, offering for this reason a 

 superior horizontal and transverse face and a posterior 

 vertical face, which makes a division of the posterior con- 

 cavity of the thorax; these two faces being separated by a 

 transverse ridge formed by t/ieir meeting. Abdomen always 

 sessile, conical, truncate at its base. (The first abdominal 

 segment less coarsely punctured than the 2d, more smooth.) 



Among the insects of this division the forms are very thickset, 

 short, and stubbed. The clypeus of the females is widened and 

 rounded at the summit, as wide as long, pear-shaped, and truncate 

 at the extremity; the angles of the truncation are often a little 

 salient, dentiform, and sometimes the clypeus appears bidentate 

 by reason of a little fossette which occupies its extremity. 

 Among the males this piece is most often polygonal, truncate, as 

 wide as long. 



The thorax is very cubical, with little or no retraction behind. 

 The metathorax never prolongs itself beyond the post-scutel, but 

 is briefly truncate; its truncation encroaches strongly upon the 

 post-scutel and gives birth to a smooth plate which occupies most 

 of its width; this plate is polygonal, often armed with two lateral 

 teeth, and bordered by some sharp or blunted ridges, which 

 become , ispecia i ly salient upon the latero-superior borders, where 

 they fonn on each side a sort of arcade, and are often terminated 

 by a projection, separated from the post-scutellum by a fissure. 

 Among these species having a thorax very square and widened 

 behind, this character is well developed, but the ridges do not 

 bend at the middle to form a re-entering angle under the angle 

 of the post-scutel (as among the Ancidrocerus), but are effaced 

 at the entrance. 



The post-scutellum seen above is almost linear, truncate verti- 

 cally, and its posterior face makes a division of the posterior plate 

 of the thorax; its ridge is sharp and often crenulate. The 



