102 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
the same, the outer anterior toe appears decidedly longer than the posterior. The specimen is, 
however, in such a defective state of preservation as to render it almost impossible to ascertain 
its true characters. 
Picus thyroideus, upon which Pilumnus was founded, differs a little from P. varius in a 
longer, more attenuated, and slenderer bill; more curved culmen ; and less prominent lateral 
ridge. The outer toes too are more nearly even. 
The genus Pilumnus , originally established by Bonaparte, is used in the Crustacea , and 
cannot, of course, be again employed. In supplying a new name, I consider the old Picus 
varius as the type instead of thyroideus , which may possibly constitute the type of a distinct 
genus. Reichenbach takes Mr. Cassin quite severely to task for not recognizing a Colaptes in 
his Picus thyroideus. There is, however, nothing of the peculiar features of Colaptes in the bill, 
and hut little in the coloration. In the latter respect it is more like Centurus , hut still suffi¬ 
ciently different to justify Bonaparte in combining it with the Picus varius and ruber. 
The species of Sphyrapicus, in respect to coloration, are divisible into two sections, the one 
with S. varius as the type, the other embracing only S. thyroideus. The following diagnosis 
will serve readily to distinguish them. All have the central line of the belly yellow, and the 
upper tail coverts white. 
A. No transverse bars on the body. Middle of the back longitudinally spotted with whitish. 
Upper tail coverts, outer half of middle and greater wing coverts, and line from the nostrils 
(including the nasal feathers) under the eye, white ; middle line of the belly yellow. 
Crown red, bordered all around with black. A post-ocular white stripe ; chin and throat 
broadly red ; a patch of black on the breast; outer and inner tail feathers varied with 
white. S. varius. 
Head, neck, and sides of breast and body black. A post-ocular white stripe ; nar¬ 
row line of chin and throat red. Tail feathers entirely black. Back scarcely 
spotted. S. williamsonii. 
Head, neck, and breast red. No post-ocular white stripe. Innermost tail feathers only 
varied with white. S. ruber. 
B. Everywhere, except on the head and neck, upper tail coverts and middle line of belly, 
transversely banded with black and whitish. No white (or red ?) on the head. 
Head and neck light brown; a large black pectoral patch.*. S. thyroideus. 
Comparative measurements. 
Catal. 
No. 
Species. 
Locality. 
Sex. 
Length. 
Stretch 
of wings. 
Wing. 
Tail. 
Tarsus. 
Middle 
toe. 
Its claw 
alone. 
Bill 
above. 
Along 
gape. 
Specimen 
measured. 
2107 
o 
7.64 
4.90 
3.50 
0.80 
0.84 
0.34 
1.00 
1.00 
V 
8.50 
14.75 
5.00 
782 
7.44 
4.86 
3.14 
0.86 
0.80 
0.34 
1.00 
1.04 
2076 
<? 
7.52 
4.80 
3.24 
0.78 
0.84 
0.32 
0.96 
1.04 
do. 
8.25 
15.25 
4.84 
6042 
7.98 
5.06 
3.56 
0.90 
0.84 
0.32 
0.94 
0.98 
5621 
7 40 
4.78 
3.42 
0.84 
0.86 
0.34 
0.90 
0.96 
6038 
a 
8 00 
4.'4 
3.48 
0.80 
0.90 
0.36 
0.96 
0.96 
3899 
O 
7.98 
4.86 
3.44 
0.88 
0.88 
0.38 
1.00 
1.06 
Skin. 
8804 
O' 
7.64 
4.92 
3.76 
0.84 
0.88 
0.30 
0.98 
0.98 
do. 
o 
A 
9.00 
15.25 
5.00 
9344 
o 
o 
7 60 
5.24 
3.30 
0.88 
0.82 
0.40 
1.06 
1.04 
3903 
V 
o 
8.80 
5.36 
4.06 
0.84 
0.86 
0.30 
1.20 
1.20 
8807 
V 
Q 
7.10 
4.32 
3.44 
0.84 
0.84 
0.34 
0.90 
0.96 
8.75 
15.25 
4.50 
