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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. 



Picm thyroideus, upon which Pilumnus was founded, differs a little from P. varius in a 

 longer, more attenuated, and slenderer hill ; 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 Picas 

 varius as the type instead of thyroideus, which may possibly constitute the type of a distinct 

 genus. Eeichenbach 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 but little in the coloration. In the latter respect it is more like Centurus, but 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 8. 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. 



