STUDIES IN NEOTROPICAL MALLOPHAGA—CARRIKER 195 
segments I to III. The chaetotaxy of the female is practically the 
same as in the male, with the exception of segment VII. 
I was much surprised to find among these specimens of Heptapsus 
a second species which is larger than nothocercae and which has the 
male genitalia quite different. Both species were taken together on 
two individuals of the same host. It is described below. 
HEPTAPSUS INEXPECTATUS, new species 
Figure 23, k 
Types.—Male and female, adults, from Nothocercus bonaparti, col- 
lected by the author at Tierra Nueva, Sierra Perij4é, Colombia, July 
12, 1941; in U. S. National Museum. 
Diagnosis.—Differs from H. nothocercae as follows: Total length 
considerably more in both sexes (male, 1.82 against 1.18; female, 1.45 
against 1.16); the head in the male is longer but very little wider, 
either at frons or temples, while in the female it is about the same pro- 
portion but larger; the thoracic segments are of practically the same 
length in both sexes but uniformly wider (than in nothocercae), while 
the abdomen is both longer and wider in both sexes. In the female 
of nothocercae the anterior margin of abdominal segment V is slightly 
concave, and that of VI is straight, while in the new form both V 
and VI are strongly arched, being pushed forward medially by the 
longer segment VII. The structure of segment VII in the female 
is also slightly different (see fig.). The chaetotaxy seems to be about 
the same in both species. 
The most striking difference is in the male genitalia. In notho- 
cercae the paramers are so completely fused with the basal plate that 
they seem to be merely a continuation of it, no trace of suture being 
visible. In inexpectatus the paramers, while strongly fused to the 
basal plate, nevertheless clearly show the line of suture on the sides. 
while they are short, straight, and tapering to a narrow, truncated 
tip (not broad and bifurcated as in nothocercae). The endomeral 
plate is small, poorly chitinized and pigmented, and difficult to differ- 
entiate. The species is represented by two males and five females, 
while in the same lot of specimens were four males and six females 
of H. nothocercae. 
Remarks.—These two species (H. nothocercae and H. inexpectatus) 
are remarkably alike superficially. The females, except for size and 
different shape of abdominal segments V and VI, would be impossible 
to differentiate. The males are even more similar than the females, 
except for genitalia and proportions of head. 
