50 BREWSTER AND BANGS—A NEW AITHURUS [P-¥-EZC. 
tail—two middle rectrices dark bluish green (coppery green in A. folytmus), 
two outer rectrices deeply tipped with white, otherwise purple-black slightly 
edged and tipped with green; bill, slender, short, wholly black. (The bill in 
dried specimens of the adult female of 4. polytmus is yellowish brown on basal 
half of upper mandible and yellow on basal half of lower mandible, these colors 
shading gradually into the black tip.) 
The young male differs from the adult male in lacking the elongation of the 
second rectrices and in having the middle rectrices green; crown much spotted 
with green; under parts mixed with grayish; shade of green throughout as 
in the adult; bill as in the adult. (The bill in the young male of 4. polytmus 
has a deeper black tip than in the adult, and the culmen is often brownish, 
not yellow; the basal portion of the lower mandible is always yellow, but in 
very young individuals it is sometimes darker and more buffy than in the 
adult.) 
Size.— Judged by the series of skins of the two species, made in the same 
style by one collector, A. scztu/us is a smaller, more delicately built bird, witha 
smaller head, than A. polytmus. 
MEASUREMENTS (in millimeters). 
Aithurus scitulus Brewster and Bangs. 
WING ExposED CULMEN 
Average Smallest Largest Average Smallest Largest 
20 adult males 62.95 60.5 64.0 19.20 18.6 20.2 
20 adult females 54-18 53a5 56.0 19.32 18.6 20.0 
20 young males 60.60 60.0 61.5 18.98 18.4 19.4 
Aithurus polytmus (Linn.) 
: WING ExposED CULMEN 
Average Smallest Largest Average Smallest Largest 
19 adult males 66.03 65.0 67.0 20.52 20.0 21.0 
18 adult females 57-09 56.50 9-5 20.74 20.0 21.4 
12 young males 62.50 61.0 64.0 20.48 20.0 21-2 
(Note.— With the females it is not always possible to tell the 
age by the skins, and the range in the above measurements is 
probably greater, therefore, than it would be if this could be done 
with certainty. The young males, here measured, are of various 
ages, ranging from quite young individuals to those which are 
beginning to take on the characters of the adult; the specimens 
of A. scitudus are, however, much more nearly of an age than are 
the specimens of A. polytmus.) 
