422 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



fourth as long as wing, the upper third feathered in front, the acro- 

 tarsium with a continuous series of large, overlapping, transverse 

 scutella, the planta tarsi also with a continuous series of large trans- 

 verse scutella, the intervening lateral spaces with rather large irregu- 

 larly hexagonal or rhomboidal scales, then much smaller on lower 

 portion, the extreme lower part of acrotarsium and base of toes with 

 more roundish scales; middle toe (without claw) less than half as 

 long as tarsus, the lateral toes much shorter, the outer slightly longer 

 than the inner; hallux decidedly shorter than inner toe, very strong; 

 upper surface of toes with large transverse scutella, their edges 

 prominent; claws conspicuously graduated in size, that of the hallux 

 (largest) exceeding the digit in length, that of the outer toe (smallest) 

 much less than half as long. 



Plumage and coloration. — Plumage in general full and soft, as in 

 Harpia, loral region rather scantily covered with small, short feathers 

 with bristlelike tips, the latter larger along anterior margin; eyelids 

 with small but distinct lashes; malar apex with rather long antrorse 

 or semierect bristles; feathers of posterior portion of head and neck 

 elongated, as in Harpia, but much narrower, with more narrowly 

 rounded tips; secondaries greatly developed, relatively very broad, 

 but the longest falling considerably short of tips of longest primaries ; 

 feathers of thighs short and dense (as in Harpia), continued below, in a 

 broad angle, over upper portion (about upper third) of acrotarsium. 

 Adults with upperparts and chest mostly blackish, the head usually 

 grayish, paler on throat; underparts of body barred or banded with 

 white and blackish or rufous, in varying relative proportion, rarely 

 almost immaculate white; tail crossed by about three to five bands of 

 mottled grayish. Young with head, neck, and underparts white or 

 mostly so, and upperparts mottled gray and blackish. 



Range. — Tropical South America, north to Honduras (two species, 

 which may eventually prove to be color phases of one form). 



KEY TO THE SPECIES OF MORPHNUS 



a. Abdomen, or at least under tail coverts, with black bands (Panama to Bolivia). 

 h. Abdomen heavily barred with black. 

 c. Tail with 4 broad black bands; upperparts black. 



M. taeniatus, ad. (p. 427) 

 cc. Tail with 5 broad black bands; upperparts fuscous to fuscous-black. 



M. taeniatus, imm. (p. 428) 

 hh. Abdomen unbarred or with only a few blackish spots on lower abdomen and 



thighs M. taeniatus, juv. (p. 428) 



aa. Abdomen and under tail coverts with no black bands (Honduras to Argentina). 

 h. Upperparts generally whitish; tail with 10-12 bars of blackish. 



M. guianensis, juv. (p. 425) 

 bb. Upperparts generally blackish, plain or mottled with grayish; tail with 4-5 

 black bars. 



