486 PROCEEDINGS OF THE ACADEMY OF 



3. MlCRASTUR GUERILLA. 



Micrastur guerilla, Cassin, Pr. Acad. Nat. Sci. Phila. 1848, 87 (Young) ; 

 Journ. Phil. Ac. I, 1850, pi. xl. Gray, Gen. B. I, 1849, 28; Hand 

 List, I, 1869, 31. Bonap. Consp. I, 1850, 30. Strickl. Orn. Syn. I, 

 1S55, 123. Scl. and Salv. P. Z. S. 1869, 368; 1870, 214-838; Norn. 

 Av. Neotr. 1873, 120. Salvin, P. Z. S. 1870, 214-16. Skarpe, Cat. 

 Diurn. Ace. Br. Mus. 1874, 79. 

 "Micrastur concentricus," Scl. P. Z. S. 1856, 285. 

 "Micrastur gilvicollis," Scl. P. Z. S. 1858, 96. Scl. and Salv. Ibis 1859, 



218. Lawr., Ann. N. T. Lye. VII, 1861, 317. 

 "Micrastur xanthothorax," Scl. P. Z. S. 1859, 368. 



" Micrastur r uficollis," Ridgw. Pr. Boston Soc. N. H., May, 1873, 78. (In 

 part.) 



Sab. Middle America, from Vera Cruz, Eastern Mexico, to 

 Ecuador (Guayaquil). 



Sp. Char. Wing, 6.50-7.10; tail, 6.90-7.50; culmen, .55-. 70 5 

 tarsus, 2.20-2.50 ; middle toe, 1.10-1.25. 



Adult. Plumbeous phase: Above uniform plumbeous, the 

 wings slightly browner, and the tail blackish. Tail narrowly 

 tipped with white and crossed by 3-4 narrow oblique bars of white 

 or dull brownish-gray (broader, and always white, on the inner 

 webs). Cheeks and throat ash-gray, the latter becoming lighter 

 centrally. Other lower parts white, barred everywhere, in very 

 regular transverse rays, with dark-plumbeous. Brown phase : 

 Similar, but entire back and wings chocolate, umber, or sepia- 

 brown, contrasting strongly with the plumbeous of the head and 

 neck ; jugulum more or less tinged with brown. 



Young. Spotted phase: Above dark clove-brown, the crown 

 and nape brownish-black ; nape crossed by a collar of white spots, 

 sometimes continuous and conspicuous, often nearly concealed ; 

 scapulars and entire wings indistinctly barred, or transversely 

 spotted, with paler, more rusty-brown, these bars being most con- 

 spicuous on the tertials. Tail dusky-black, tipped with white, 

 and crossed by 4-5 narrow bars of the same. Throat white, this 

 extending upward behind the dark-brown auriculars in the form 

 of a half crescent; remaining lower parts buffy-white or deep- 

 bull' barred (less regularly and finely than in the adult) on the 

 breast and sides with dusky-brown rarely barred over the whole 

 surface. Plain phase: Similar, but the pale-rusty bars on wings 

 and scapulars obsolete, and the colors generally clearer; usually 

 less heavily barred beneath sometimes immaculate. 



