74 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY GENERAL REPORT. 



This species, in addition to the names cited above, is also sometimes called Correo camino. 

 It is common in Texas and California, and always excites attention by its large size and peculiar 

 habits. In a very large series of this species I find great variations in size, although but little 

 in color. As a general rule, however, skins from California are considerably larger than those 

 from Northern Mexico and Texas. 



The difference between this species and G. affinis of Hartlaub are very appreciable. The latter 

 is decidedly smaller ; the bill is much smaller, shorter, and both culmen and commissure are 

 cuived almost from the base of the bill, instead of straight nearly to the tip. The culmen is 

 shorter than the head instead of longer,- and the nostril is opposite the middle of the commissure 

 instead of decidedly posterior to the same point. The tarsi are only about two inches long ; the 

 culmen 1.30 inches. The tertials and outer surface of the wings are glossed with coppery violet 

 instead of green ; the lateral tail feathers with green instead of blue. The under parts are 

 nearly uniform brownish yellow or whitish, the sides of the breast alone with a few sharply 

 defined, longitudinal streaks of black, instead of brownish cinnamon; breast feathers edged 

 with hoary white, and much streaked centrally, though narrowly, with black ; the belly dirty 

 white. The length is about 18 inches ; the wing 5.50 ; the tail 9.15. 



If Hartlaub's quotation of 1829, as the date of the Saurothera californiana, Lesson, be correct, 

 this name will take precedence among the more modern ones. Should this not be the case, then 

 the next in order will probably be that of Wagler. I am unable to say what the relationships 

 of G^. vfifox of Karwinski, (Miinchner Grelehrte Anzeigen, III, 1836, 95,) may be, not having 

 this volume at hand for reference. 



The Phasianus mexicanus of Gmelin, I, 1788, 741, based on the Hoitlallotl of Hernandez, 

 (Nova Anim. 1690, app. 25,) in all probability refers to a species of Geococcyx, but it is entirely 

 impossible to say which. Hernandez was most likely to have met with the southern species, or 

 affinis. Still, in the entire impossibility of ever coming to a decision, either in reference to 

 Phasianus mexicanus, or Upupa mexicana of Gmelin, it seems much better to drop the consid- 

 eration of these names and to confine investigations to more modern authors. 



