BIRDS OF NORTH AND MIDDLE AMERICA. 207 



M. 7'ufo-axiUaris) always lay their eggs in the nests of other birds, their 

 habits in this respect being quite the same as those of the t3^pical North 

 American species {3£. ater), the third {M. hadkis) always builds its 

 own nest and rears its own young in the usual fashion. This fact, 

 taken in connection with the very different proportions of the prima- 

 ries and the peculiar coloration, alluded to above, may necessitate the 

 adoption of the name Aglaioides Cassin for a genus containing M. hadius 

 and M. fringillarius. 



KEY TO THE SPECIES AND SUBSPECIES OF MOLOTHRUS. 



a. General color glossy black. 



b. Head and neck brown. {Molothrus ater, adult male.) 

 c. Larger (wing averaging 110.5, tail 75.2, culmen, from base, 18). (More 

 southern British provinces to plateau of Mexico.) 



Molothrus ater ater, adult male (p. 207) 

 cc. Smaller (wing averaging 100.3, tail 68.8, culmen, from base, 16.3). (Mexico 

 and adjacent portion of United States. ) 



Molothrus ater obscurus, adult male (p. 210) 

 bh. Head and neck glossy violet-black, like rest of plumage. (Guiana; Venezuela; 

 Trinidad; Tobago; Grenada and Grenadines. ) 



Molothrus atronitens, adult male (p. 211) 

 aa. General color grayish or brownish. (Adult females and young.) 



b. Longest jirimaries exceeding secondaries by much more than length of tarsus. 

 {Molothrus ater, adult female.) 

 c. Larger (wing averaging 101.1, culmen 16.) 



Molothrus ater ater, adult female (p. 207) 

 cc. Smaller (wing averaging 90.7, culmen 15.) 



Molothrus ater obscurus, adult female (p. 210) 

 bb. Longest primaries exceeding secondaries by not more than length of tarsus. 



Molothrus atronitens, adult female (p. 212) 



MOLOTHRUS ATER ATER (Boddaert). 

 COWBIRD. 



Adult male. — Head, neck, and upper chest plain brown (varying 

 from broccoli brown or drab to warm clove brown); rest of plumage 

 glossy greenish l)lack, the gloss usually more violet (often distinctly 

 so) on upper back, next to brown of hindneck; bill, legs, and feet 

 black; iris brown; length (skins), 167.6-194:.3 (179.3); wing, 105.4- 

 115.8 (110.5); tail, 70.1-80 (75.2); culmen, from base, 17.3-19.6 (18); 

 depth of bill at base, 11.1-12.7 (12.2); tarsus, 24.1-28.2 (26.7); middle 

 toe, 16.5-20.8 (18.5).^ 



Adult female. — Above brownish gray, faintly glossed with greenish, 

 the feathers with darker centers and blackish shaft-streaks, especially 

 on back; wings and tail more dusky brownish gray with paler edgings, 

 these nearly white on longer primaries; under parts paler brownish 

 gray or hair brown, usually more or less distinctly streaked (nar- 

 rowly) with darker, the chin and throat much paler (sometimes almost 



^Fourteen specimens. 



