ICHNEUMON-FLIES — GELINAE : MESOSTENINI 179 



a white spot but in some exotic species margined with white or yellow; 

 ovipositor sheath varying from about 0.4 to about 0.82 as long as 

 front wing; ovipositor somewhat compressed, its point usually sunple 

 or somewhat sagittate. 



Trachysj^hyrus is best represented in the Holarctic area and in the 

 southern half of South America. There are also some species in the 

 Oriental and Ethiopian regions. The genus contains the central core 

 of a large group of species from which the more obviously divergent 

 groups have been split off as genera. The process of splitting will 

 probably proceed further when the world fauna is more thoroughly 

 understood, but it might also be reversed to some degree. The Nearc- 

 tic species included in Trachysphyrus are obviously related, and at 

 present there does not seem to be a good reason to subdivide them as 

 genera, or even as subgenera. The stronger groupings of the Nearctic 

 species, however, are recognized as species groups. Some of the gen- 

 era closely related to Trachysphyrus are: Hahrocryptoides, Reptatrix, 

 Lanugo, Chromocryptus, Corny socry plus, and the non-Nearctic Syne- 

 chocryptus, Cryytopteryx, Zonocryptus, and Neodontocryptus. 



Trachysphyrus is one of a group of related genera that are charac- 

 teristic of more open habitats with sparser vegetation than most other 

 Mesostenini, in our fauna the genera related to Trachysphyrus in 

 morphology and habitat being Compsocryptus, Joppidium, Lanugo, 

 and probably Chromocryptus and Beptatrix. Comp>socryptus, Joppid- 

 ium, and some species of Trachysphyrus are probably parasitic on 

 larvae feeding on grass or drouth-resistant herbage and pupating in 

 the soil. Next to nothing, however, is actually loiowii about these. 

 Lanugo and Chromocryptus seem to have taken to hosts that feed and 

 spin cocoons in the bushes. Most species of Trachysphyrus give off 

 a strong, musty smell when captured, reminiscent of stale chocolate 

 and different from the characteristic smell of Coccygomimus, Meso- 

 leius, Exochus, alomjdnes, etc. Most of our species occur in the west- 

 ern half of the continent. 



The Nearctic species have recently been revised by Dr. H. D. Pratt 

 (1945, Amer. Midi. Nat., vol 34, pp. 562-661). Since his descriptions 

 are rather detailed and can be referred to if need be, the descriptions 

 below are often sketchy or onl}^ diagnostic. 



In reviewing Pratt's w^ork on the genus, we have studied all but 

 three of the types, and have seen a number of his paratypes and deter- 

 mined specimens in various collections. In the course of the review, 

 we found that occasionally Pratt confused more than one form under 

 a name, but that for the most part his determinations would agree 

 with our o\Yn. Below, we have recorded and mapped only the speci- 

 mens seen by ourselves; these are usually sufRcient to show the distri- 

 bution of the species and subspecies. Further localities are to be 



