TERETRISTIS. 



233 



1st and longest primaries, .50 ; length of bill from forehead, .60, from nostril, 

 .37 ; along gape, .61 ; tarsus, .80 ; middle toe and claw, .Q6 ; claw alone, .20 ; 

 hind toe and claw, .45 ; claw alone, .21. 



This beautiful and hitherto undescribed species is quite similar to 

 G. venustus in appearance, but differs in a much longer, broader, 

 and more rounder tail. The wing is much graduated ; the 4th and 

 5th quills nearly equal ; the 3d a little shorter ; the 2d about equal 

 to the Tth ; the 1st shorter than the secondaries. The principal 

 difference in coloration consists in the absence of the black pectoral 

 collar (although a few concealed spots may be considered as repre- 

 senting it) ; in the pure white of the sides of the breast, instead of 

 plumbeous ; in the narrow whitish bands across the wings ; the 

 greater amount of white on the tail, etc. From pelzelnii it is distin- 

 guished by the plumbeous crown and white tips of the tail feathers. 



This bird is one of a number of new species discovered, during 

 the past winter, by Col. Grayson, on one of the Three Marias, a 

 group of Islands off the coast of Mexico, about eighty miles from 

 San Bias ; and I cannot more appropriately dedicate it than to Mrs. 

 Grayson, to whose encouragement Col. Grayson owes so much of the 

 persistency and success with which he has prosecuted the study of 

 the ornithology of California and western Mexico. 



TERETRISTIS, Cabams. 



Teretrisds, Cabanis, Jour. Orn. Ill, 1855, 475. (Type An abates fernan- 

 diiice, Lemb.) 



Bill slender, rather deep and compressed from the base, not quite so long 

 as the head ; the outlines of upper mandible considerably decurved, and 

 without notch at tip ; the gonys straight. Rictal bristles short and incon- 

 spicuous, not reaching the nostrils. Some scattered bristles in the chin. 

 Nostrils rather elongated, without membrane above them anteriorly, the frontal 

 feathers coming up close. Wings shorter than the slightly rounded tail. 

 First quill shorter than outer secondaries ; 2d about equal to 7th ; 3d and 4th 

 equal and longest. Tail slightly graduated, the feathers acuminate. Inner 

 toe with basal joint cleft rather more than half; tarsi short, but little longer 

 than middle toe and claw ; the scutellse distinct, or else fused on the outside ; 

 claws short, considerably curved. Sexes similar. No spots on the tail. 



This is another genus the precise position of which is somewhat 



