62 



bulletin: museum of comparative zoology. 



beyond the middle, but with no lateral ones behind the spiracle which is placed 

 distinctly before the middle. Second to sixth abdominal segments each about 



equal in length, and each two-thirds as long as 

 / *\ the first. Wings hyaline, the stigma rather long, 



lanceolate, fuscous. Venation fuscous, the veins 

 stout. Areolet absent, the recurrent nervure 

 received one-half the length of the transverse 

 cubital vein beyond the base of the latter; sub- 

 median cell longer than the median by two- 

 thirds the length of the transverse median 

 nervure which is strongly oblique. Marginal 

 cell rather small and narrow, pointed, the 

 second section of the radius two and one-half 

 times as long as the first; first recurrent nervure 

 broken just below the middle. Posterior legs 

 rather stout, black, their tibiae apparently white 

 except at base and apex. 





Fig. 46. — Tryphon florissan- 

 tensis, sp. nov. Type. 



Described from a single specimen col- 

 lected by Mr. S. A. Rohwer at Station 13. 

 Type in the Amer. Mus. Nat. Hist. 



Orthocentrus Gravenhorst. 



Two species are known from Florissant, one here described as new 

 and the other characterized in a previous paper (Brues :06). They 

 are separable as follows: 



Key to the Florissant species of Orthocentrus. 



1. Posterior tibiae scarcely longer than their femora, radius of w'mg 

 evenly curved, submedian cell but little longer than the median. 



0. primus Brues. 

 Posterior tibiae one-third longer than their femora; radial vein 

 strongly bent above the areolet, elsewhere nearly straight, 

 submedian cell considerably longer than the median. 



O. defossus, sp. nov. 



Orthocentrus defossus, sp. nov. (Fig. 47.) 



Sex? Length probably about 6-7 mm., the insect completely bent on itself. 

 Black or dark colored, the abdomen beyond the petiole brownish yellow. 

 Legs fuscous; at least the posterior pair with the trochanters considerably 



