126 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95 
prothorax is wider anteriorly, and the pterothorax extends farther 
laterally from the sides of the abdomen; the last abdominal segment 
is more rounded posteriorly and less protuberant. 
The chaetotaxy and the markings of the abdominal pleurites seem 
to be about the same. It is unfortunate that no male is available, 
since the genitalia would undoubtedly present distinguishing char- 
acters. Three additional females were taken on the same bird. 
MEASUREMENTS OF MEGAGINUS EMARGINATUS 
Pi eed arr emarginatus (female) 
Structure 
Length Width Length Width 
LBL OYO barley he ian OHA OMI Canin UU WH cb Naat Sr Us INL MaDe OE DOS ity Sete eich acee ee 1. 26 
1S If Sf2 9 Apa na EAC He NOURI, EY NOS AL 0. 39 0. 51 0. 444 0. 585 
Rd ODE ALO) Gp2 D. Copeenp ER YA a UN ROPER aI Sen Ne pe la EL URSA 0.118 0. 28 0. 108 0. 309 
PPerochorea xe who Re 20S a vO AC LL eas oe en 0. 202 0. 38 0. 222 0. 423 
ANY of 0 Key 0 12) & Wes AV Lae A GAN a SU aa Dot OL 0. 57 0. 54 0. 68 0. 618 
MEGAGINUS EMARGINATUS EXCAVATUS, new subspecies 
FIGURE 8, b-d 
Types.——Male and female, adults, from Crypturellus sour incon- 
spicuus, collected by the author at Santa Ana, Rio Coroico, Bolivia, 
July 30, 1934; in collection of author. 
The series of 4 males and 12 females, from which these types 
were selected, was tentatively placed under &/. ec. emarginatus (Car- 
riker, 1936, p. 100), but a more careful study of them reveals differences 
much too great to be disregarded. 
Diagnosis.—More closely related to emarginatus than to quadri- 
thorax, having the shape of the prothorax and the pattern of markings 
on pleural plates similar to the former but differing radically from 
both in the shape of the head and the frontal emargination. 
The head is wider and shorter, with clypeus narrower; the frontal 
emargination wider and twice the depth, while the bipartite tips of 
the frons are more pointed. It resembles /. e. sordidus in shape of 
head, although the new form has the head even wider, but it differs 
from sordidus in the narrower clypeus, with tips of frons more 
pointed, and in deeper and wider emargination, as well as in the mark- 
ings of the pleural plates. 
It differs from J. e. lataclypeus in the same way as from the other 
races of emarginatus, viz: in the much narrower clypeus, pointed frons, 
and deep frontal emargination; in fact, there is no other form of the 
genus possessing this type of clypeus ane cen emargination (table 
of measurements follows dissimilis). 
