210 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



equal to or longer than wing, strongly rounded (graduation about 

 equal to or more than length of middle toe without claw), the rectrices 

 very broad. Tarsus equal to or longer (usually decidedly longer) than 

 exposed culmen (a little more than one-fourth to nearly one-third as 

 long as wing), rather slender, the acrotarsium distinctly scutellate; 

 middle toe (without claw) about two-thirds as long as tarsus; lateral 

 toes unequal, the inner (without claw) reaching to subterminal joint 

 of middle toe, the outer slightly beyond; hallux shorter than inner toe 

 but much stouter; claws normal in size and curvature, that of the 

 hallux decidedly shorter than its digit; basal phalanx of middle toe 

 united to that of outer toe by about the basal half, almost wholly free 

 from that of inner toe. 



Coloration. — Upper parts plain grayish blue or bluish gray, the 

 under parts similar, or with throat, chest, breast, and abdomen white. 



Nidification. — (Unknown . ° ) 



Range. — Mexico and highlands of Guatemala. (Three species.) 



KEY TO THE SPECIES OP MELANOTIS. 



a. Under parts chill slaty blue, like upper parts. 



b. Darker in color; larger (except bill and feet) , with relatively longer tail and shorter 

 bill (adult male averaging wing 112.4, tail 125.3, exposed culmen 2?>.l). (Cen- 

 tral and southern Mexico.) Melanotis caerulescens (p. 210) 



bb. Paler; smaller (except bill and feet), with relatively shorter tail and longer bill 

 (adult male averaging wing 107.7, tail 108, exposed culmen 26.6). Tres 



Marias Islands, western Mexico.) Melanotis long-irostris ( p. 212) 



aa. Under parts white (except sides, flanks, and under tail-covert,'^). (Highlands of 

 Guatemala,) Melanotis hypoleucus (p. 212) 



MELANOTIS CAERULESCENS (Swainson). 

 BLUE MOCKINGBIRD, 



Adult male. — Pileum and hindneck dull grayish blue, slightly paler 

 on forehead and superciliary region, the feathers dusky basally (and to 

 a certain extent laterally) , producing a more or less distinctly streaked 

 appearance; rest of upper parts plain dark grayish blue (between 

 indigo and slate-color), the shafts, and often a narrow streak on web 

 along shafts, of rectrices and remiges black; under side of rectrices and 

 remiges slate-black; loral, suborbital, auricular, and malar regions 

 black, producing a conspicuous patch on side of head, the two of oppo- 

 site sides connected on cliin ; feathers of throat and chest semi-lanceo- 

 late, light grayish blue, dusky at base and edges, producing a streaked 

 appearance; rest of under parts plain dull grayish blue, slightly paler 

 than that of upper parts; bill black; iris brown; legs and feet black 

 or dark brown; length (skins), 252-273 (259); whig, 108-119 (112.4); 

 tail, 116-132 (125.3); exposed culmen, 21-25 (23.1); tarsus, 28.5-33 

 (30.7); middle toe, 21-23 (22).^ 



a See The Ibis, 1859, 7. & Eleven specimens. 



