STUDIES IN NEOTROPICAL MALLOPHAGA—CARRIKER 171 
male, and with temples narrower in the female than in the male (just 
the reverse of feres, which is typical of the sexual dimorphism found 
in this and other groups with temples of this type). 
RHYNCOTHURA CHACOENSIS, new species 
FIGURE 18, e-9 
Types.—Male and female, adults, from Vothoprocta cinerascens, col- 
lected by the author at Villa Montes, Bolivia, November 6, 1936; in 
collection of author. 
Diagnosis.—In this distinct species we have a type of head similar 
to that of Heptapsogaster tesselatus, with the six internal projections 
on the frons and the heavy templar incrassations, but there is no sign 
of the tessellated dorsal surface, the serrated margins of the occiput 
and mesothorax, or the peculiar structure of abdominal segment VII 
found in that species, while the type of the genitalia is quite distinct. 
The whole insect is small, about the size of 2. menuta, with the head 
large and body short and wide. The prothorax is short and wide, 
with convex, divergent sides and sharp lateral angles with a spine; the 
structure of the mesometathoracic segments is clearly illustrated in 
the figure, as well as the chaetotaxy. 
The abdomen in both sexes is oval, short, and broad and eat little 
longer than wide (0.69 by 0.63 and 0.70 bay 0.62). The structure of 
the paratergals is somewhat obscure. In the male they seem to be 
clearly outlined on the inner margins but with another sclerite show- 
ing within the pleurites on segments II to VI. This may be a ventral 
extension of the pleurite, more faintly pigmented than the dorsal 
portion, and with irregular internal margin. There is a small, more 
deeply pigmented, round or oval spot on pleurites I to V. These are 
not the spiracles, which are located in the paler, inner portion of the 
plate. The tergites are continuous, but narrow and faintly pig- 
mented, and there are no apparent sternites. 
The chaetotaxy of the whole body is scanty (see figure). The legs 
are small, with femora and tibiae short and thick and of about equal 
length and with some stout, longish spines, but not so many as in 
subteres. The trochanters are also well developed on all three legs, 
while the claws are long and very slender. The male genitalia are 
simple in structure, the short, thick paramers, sharply bent inward 
apically and tapering to their narrow tips; the endomeral plate is 
deeply inserted within the basal plate and is almost as long as the 
paramers, with broad, rounded tip, destitute of projections of any 
kind. Like so many species of this genus, there is a minute bristle set 
in a small pit on the outer edge of the paramers near their tips. 
The head and body of the female are very similar to those of the 
male, except for the dimorphic antennae; the incrassations along the 
