NATURAL SCIENCES OF PHILADELPHIA. G9 



crinitus ; another, non-migratory, set spreading for a short dis- 

 tance northwestward to form the local race cooperi, and yet 

 another, chiefly spreading southward throughout the greater part 

 of South America, forming the variety irritabilis. It is little, if 

 any, beyond the southern terminus of cinerascens, forms the 

 southern limit of laiorencei, and constitutes the northern boundary 

 of nigriceps and tyrannulus (ferox). In fact, every continental 

 species treated of in this paper, excepting phseocephalus, occurs 

 between Tehuantepec and Panama; this is the very centre of the 

 genus. 



Specimens examined, twelve. 



3. Myiarchus cinerascens. 



Tyrannula cinerascens, Lawr., A. L. N. Y. v, 1851, 109 (descr. orig.). 

 Myiarchus cinerascens, Scl., Ibis, 1859, 121, 440; P. Z. S. 1859, 384; 



C. A. B. 233 (excl. syn. Tyr. mexicana, Kaup). 

 Myarchus mexicanits, Bd., B. N. A. 179 (sed non Tyr. mex., Kaup) ; 



Coues, P. A. N. S. P., 1806, 59 ; Coop., B. Cal. i., 316, cum fig. 

 Myionax mexicanus, Cab., M. H. ii., 74 (non Kaup). 

 M. mexicanus var. pertinax, Bd., P. A. N. S. P., 1859, 303 (Cap. St. 



Lucas). 



M. inter majores, rostro angusto, nigro; coloribus dilutis; oliva- 

 ceo-cinereus, pileo brnnnescentiore, gula ex albida cinerea, ventre 

 sensim ex albido flavo; remigibus secondariis tectricibusque ala- 

 rum superioribus albido marginatis; remigibus primariis rectri- 

 cibusque rufo-indutis ut in M. crinito, sed rufo vix in apicein 

 rectricum porrecto, et ab fusco linea eurvata segregate Statu ra 

 M. crinito par, tarsis longioribus (.80-.90), rostro angustiore 

 (.21-.3S). 



Habitat partibus Eeip. Amer. S. merid.-occid., et Mexico. 

 Utah (McCarthy). Nevada (Ridgway). N. Mexico, Arizona 

 (Cones). California (Cooper'). Cap. St. Lucas (Xantus, " var. 

 pertinax"). Texas (Couch). Mazatlan (Grayson). Mirador 

 (Sartorius). Tehauntepec (Sumichrast). Orizava (Botteri). Mus. 

 S. I., G. N. L., E. C, etc. 



Obs. One of the better marked species of this difficult group. 

 I have seen no indeterminable specimens, though I suspect that 

 questionable ones will yet appear from southwestern Mexico. 

 But the fact that the bird occurs there associated with varieties 

 of crinitus without losing its distinctive features, favors the sup- 

 position of its integrity. 

 1872.J 



