1920] Brues — The Braconid Gemis Trachypetus Gtiirin 61 



As it has been placed in the Cheloninse, I shall first compare it 

 with the members of this subfamily. Of these only Sphseropyx 

 has the abdomen petiolate with an actually flexible articulation 

 between the petiole and the post-abdomen. In that genus the 

 carapace is divided by a deep, crenulate suturiform articulation, 

 so that so far as the abdomen is concerned Sphseropyx is more like 

 a Braconine than Chelonine if we take Chelonus, Ascogaster, or 

 even Phanerotoma as typical of this subfamily. In neuration, 

 except for the truncate radial cell, Trachypetus is rather similar to 

 Sphseropyx, neither of which closely resembles any Chelonine. 

 Indeed the neuration of certain Sigalphinse is more like that of 

 these two genera except for the presence of only two cubital cells 

 and a less complete venation in the hind wing. Beyond the petiole 

 the abdomen of Trachypetus is practically unsegmented although 

 there is a trace of the suturiform articulation, a condition met 

 with occasionally in groups other than the Cheloninae and Sigal- 

 phinse. 



As to its relation to other groups of the Polymorphi, Trachypetus 

 appears to be very generalized. The abdomen is clearly petiolate 

 as in the Meteorinse and Euphorinse and Helorimorphinse with 

 which it clearly has no close affiinity. There are three cubital 

 cells and a large, complete radial cell as in the Macrocentrini and 

 Helconinse, to which latter group it shows, I think, the closest 

 affinities. Several genera of Helconinse with the abdomen clavate 

 have been described, such as Brulleia Szep. from New Guinea, and 

 Euscelinus Westw\ from Borneo, while Hymenochaonia D. T. 

 (Chaonia Cress.) from Cuba may possibly belong here. None of 

 these, however, have the segments of the post-abdomen so com- 

 pletely fused and all may be quite different from Trachj'petus, as 

 I unfortimately do not know them in nature. Spharopyx lacks 

 the thick Helconine head, which is present in Trachypetus. 



Aside from the closed marginal cell, the neuration is quite like 

 that of Cardiochiles Nees. as is also the structure of the head, 

 thorax and legs. 



Even outside the family Braconidae, the fusion of the abdominal 

 tergites into a carapace or shield-like piece occurs and this character 

 alone is in no way distinctive of the Cheloninae. Thus in the Aly- 

 siidre, Symphya has a typical carapace and even in Vanhornia, the 

 type of quite a different family with exodont mandibles the upper 

 surface of the abdomen forms a carapace. 



