176 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95 
tached on the side; fifth normal. Female with antennae filiform, with 
first, second, and fifth segments subequal, fourth the shortest. 
Head large, in female larger than combined thoracic segments; frons 
flatly rounded to circular; temples expanded laterally, with rounded 
angles, and extending little if any behind the occiput. Prothorax short 
and wide; mesothorax and metathorax almost completely fused, the 
latter overlapping the former at the sides and being almost entirely 
imbedded within the first abdominal segment. Pharyngeal sclerite 
and gland well developed. 
Abdomen elliptical in female, almost parallel-sided in the male from 
seoment I to IV; tergal plates entire and broadly separated from the 
paratergals, which are of a most unusual shape (see figure); sternal 
plates also entire, and extending completely across the abdomen, under 
the pleural plates; tip of segment VII with large opening for extrud- 
ing of genitalia, on the dorsal side of which there is a heavily 
chitinized, circular margin. Legs small, rather stout, with tibiae and 
femora about equal in length; coxae small, but trochanters well de- 
veloped; claws long and slender. 
Chaetotaxy somewhat sparse, especially on body, but most hairs are 
long. 
Genital armature with basal plate extremly long and wide (resem- 
bling Rhopaloceras), extending from tip of abdomen to posterior 
coxae; paramers minute, completely fused to tip of basal plate, and 
with their tips bent sharply inward. .The endomeres seem to consist 
of a long sac lying on top of a wide, median slit in the basal plate and 
are attached to the basal plate at the anterior end of the slot. The por- 
tion lying over the basal plate is strengthened by a heavily chitinized 
longitudinal bar on each side, while the portion of the sac which fills 
the space between the minute paramers is unpigmented, nonchitinized, 
and with thin membranous walls. 
HETEROPEOSTUS CARRIKERI (Clay) 
FIGURE 29, C-f 
Rhyncothura carrikeri Clay, Proc. Zool. Soc. London, ser. B, 1937, p. 143, fig. 6c, 
pl. 2, figs. 1, 2. (Host: Nothoprocia cinerascens.) 
I have a series of 6 males and 13 females of this interesting species, 
taken on the type host, collected by myself at Villa Montes, Bolivian 
Chaco, November 6, 1936. 
On the same individual host with the above series of H. carrikert 
were taken two new species of typical Rhyncothura. This fact, con- 
sidered in connection with the strikingly different genitalia and ab- 
dominal structure of H. carrikeri, has convinced me that carrikert 
should be placed in a new genus. 
