184 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



plain color of the adult rather closely, while the Everglade kite at 

 this age differs decidedly in heavily streaked pattern. Amadon (Amer. 

 Mus. Nov. no. 2166, 1964, pp. 3-4) after discussion of these matters, 

 in view of the general resemblance, suggests union of the two under 

 the older genus name Rostrhamus since they have no other close 

 relatives. It appears plausible to believe that the two have related 

 ancestry. But it would appear that hamatus is the more conservative, 

 perhaps more like the ancestral stock, from its smaller population. 

 Pending information on its internal anatomy, particularly the skele- 

 ton, I prefer here to emphasize the differences by listing the two in 

 separate genera. 



HARPAGUS BIDENTATUS FASCIATUS Lawrence: Double-toothed Kite; 



Gavilan Bidente 



FiGtmE 39 



Harpagus jasciatus Lawrence, Proc. Acad. Nat. Sci. Philadelphia, vol. 20, 1868 

 (April-May, 1869), p. 429. (Guatemala.) 



The irregular, double-toothed margins toward the tip of the maxilla 

 and mandible serve to identify this species in any plumage from other 

 hawks found in Panama. 



Description. — Length 290 to 330 mm. Male, above, including side 

 of head, dull gray ; wings and tail blackish, the latter with whitish tip, 

 and 3 broken cross bars, the uppermost concealed by the tail coverts ; 

 throat and upper f oreneck white, streaked with dull gray and grayish 

 black ; upper breast chestnut brown at sides, gray, barred indistinctly 

 with chestnut brown, in center; lower breast and abdomen barred 

 narrowly with white, and more broadly with gray bordered narrowly 

 with chestnut; under tail coverts and under wing coverts white; 

 under surface of wing barred broadly with white. 



Female, somewhat browner gray above; upper breast chestnut- 

 brown, with scant indication of bars ; lower surface elsewhere barred 

 broadly with chestnut brown, with gray edging reduced, and white 

 bars prominent. 



Immature, grayish above, with the concealed feather bases white 

 on head, back, and coverts ; below white, streaked broadly on breast, 

 and barred irregularly on sides and abdomen, with fuscous. 



I recorded the colors of the soft parts in a female of the typical 

 H. b. bidentatus, taken in Venezuela, as follows: Iris orange-red; 

 maxilla black, except for a dull gray area extending across the 

 posterior tooth and the base of the tomium behind; mandible dull 

 gray ; cere dull greenish ; tarsus and toes bright yellow ; claws black. 



