1963] 
Porter — Tribe Mesostenini 
19 
Xiphonychidion is a member of the Trachysphyrus Group of the 
subtribe Mesostenina of the tribe Mesostenini. Because of its large 
areolet, elongate propodeal spiracle, and almost straight mediella 
X. cyanipenne may be accounted a typical representative of this series 
of genera. From all described species, however, it differs conspicuously 
in the peculiar hooked-down ovipositor tip which indicates, perhaps, 
some rather special host. Otherwise, its closest approach is probably 
to Trachysphyrus Haliday to the vicinity of which it will run in 
Townes’ key to the Nearctic genera ( 1962, Bull. U. S. Nat. Mus. 216, 
Pt. 3), differing, however, in its strongly convex clypeus, obsolete 
notauli, postfurcal nervulus, and in the prominent sub-basal triangular 
projection of the first abdominal segment. 
The generic name is derived from the Greek xiphos — sword , onyx 
(onychos) — claw, and idion, a diminutive suffix. It refers to the 
characteristic ovipositor tip. 
In conclusion I wish to express my thanks to Dr. H. K. Townes of 
the University of Michigan whose encouragement and vast knowledge 
are a constant help to me in my work on the South American Meso- 
stenini. The synonomy given in this paper was kindly supplied by 
Dr. Townes from the manuscript of his projected Catalogue and Re- 
classification of the Neotropical Ichneumonidae. 
