220 
Psyche 
[September 
basal face gently arched and weakly sloping behind, apical face as 
long as basal and quite steeply declivous; basal trans-carina mostly 
fine and sharp but somewhat irregular medially and laterally, more 
generally weak and irregular but traceable in male; apical trans- 
carina wanting, except for the rather large and conspicuous subligu- 
late to ligulate cristae; median and lateral longitudinal carinae vague 
or absent; pleural carina weak and irregular. 1 st gastric segment : 
in both sexes with a large, bluntly triangular lateral expansion at 
base of petiole; petiole long and slender; postpetiole only weakly 
expanded, 0.9- 1.0 as wide apically as long from spiracle to apex in 
female, 0.8 in male; petiole without distinct longitudinal carinae or 
with only a trace of dorso-lateral and dorsal carinae, especially near 
apex; postpetiole with ventro-lateral longitudinal carina strong, dorso- 
lateral carina weakly suggested, and dorsal carinae vague or absent. 
2 nd gastric tergite: in both sexes with mostly superficial punctation 
and largely well-separated setae. G aster : unusually long and slender 
fusiform, somewhat compressed toward apex. Ovipositor : sheathed 
portion 0.3-0.4 as long as fore-wing; straight, moderately slender, 
strongly compressed; nodus distinct, with a small, sharp notch; dorsal 
valve with a long, almost direct taper between notch and apex; ven- 
tral valve on tip with fine, well-spaced, oblique ridges; tip 0.19-0.22 
as high at notch as long from notch to apex. 
Type Species: Nelophia compsa , new species. 
Discussion : Nelophia belongs to the subtribe Mesostenina of the 
geline tribe Mesostenini, as defined by Townes and Townes (1962, 
pp. 7, 32-33). Here its weakly arched mediella, elongate propodeal 
spiracle, and large, dorsally narrowed areolet all suggest a close 
relationship to Trachysphyrus. From Trachysphyrus Nelophia differs 
most strikingly because of its more slender habitus (in female), 
apically flattened female antenna, discontinuous erect setae of male 
flagellomeres, very high and scoop-shaped hypostomal carina, large 
expansion at base of petiole, essential absence of longitudinal carinae 
on petiole^ and slender female postpetiole. This is a combination of 
characters unapproached by any known South American species of 
Trachysphyrus , although some of these features are found singly in 
a few widely separated species representing diverse phyletic lines 
within that genus. 
The closest relatives of Nelophia are probably in the complex 
subandean and pampal north-central Argentine radiation of the genus 
Trachysphyrus , particularly among certain as yet undescribed forms 
of the Albitarsis Species Group. This genus may thus be interpreted 
