PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 475 



tinge more decided on tlie breast from the invasion of the yellow of the 

 abdomen. Wings and tail dusky, with lighter edgings. Lower parts 

 (posterior to the breast) rich lemon-yellow. Bill and feet black. Adult : 

 Crown with a central concealed patch of bright orange-red ; wing-edg- 

 ings light cinereous, sometimes (more especially in northern examples) 

 tinged with pale yellow. Female smaller than the male, the colored 

 patch on the crown more restricted, the tail less deeply emarginate, the 

 primaries less conspicuously^ narrowed at ends. Young : Crown without 

 colored central patch ; wing-edghigs pale rusty on all the coverts; upper 

 tail-coverts and rectrices likewise bordered with rusty. 



Hab. — The entire Neotropical Eegion, excepting the West Indian 

 islands ; north to Texas (Lower Eio Grande Valley) and Mazatlan ; south 

 to Buenos Ayres and Peru. 



EE3IARKS. — In all examples of this species from the South Brazilian 

 Eegion (embracing, besides Southern Brazil, Paraguay, Bolivia, and 

 Buenos Ayres), the colors are considerably darker than in any from 

 more northern localities, the throat being decidedly cinereous, and the 

 back a quite dark olivaceous gray. This series also averages consider- 

 ably larger in size, and has the tail more deeply forked. Siiecimens 

 from northern South America (Amazonian and Columbian districts) 

 show decidedly lighter throats, but are otherwise scarcely different, ex- 

 cept in their usually smaller size. To the northward, the tendency to 

 gradually lighter colors increases in direct ratio with the latitude, cul- 

 minating with the northern limit to the range of the species, in Northern 

 Mexico and tlie Eio Grande Valley of Texas. Taking examples from 

 the latter region, and comparing them with those from the extreme 

 southern range of the species (Buenos Ayres and contiguous provinces), 

 the diiference is quite obvious, although still not conspicuous, even on 

 comparison f but the points given by Professor Baird, in " Birds of North 

 America," for distinguishing his T. eoucM (the northern form) from true 

 meluHchoUcus, are found to hold good. The ample series at hand, how- 

 ever, embracing more than fifty specimens, from every j)art of the known 

 range of the species, proves beyond question the gradual transition 

 between the extremes, in intermediate localities. 



The specimens from northern South America having been named 

 satrapa by Cabanis and Heine (Mus. Heiu. II, p. 77), this name may be 

 used to characterize an intermediate form showing a tendency in a 

 nearly equal degree toward the distinctive character of both melan- 

 choliciis and coucJiL It may be observed that while examples of sa- 

 trapa agree best with the northern form in the whiteness of the throat, 

 and with the southern one in the dark shade of the wings and tail, they 

 are, as a rule, much brighter yellow beneath than either. Costa Eican 

 specimens agree more nearly with true satrapa than with Mexican exam- 

 ides (couchi). 



A rather more than ordinary amount of individual variation in this 

 species is shown by the very careful measurements of a large series. 



