110 Bangs Birds from Costa Rica and Chiriqui. 



other Panaman form proves to extend its range north to the Pacific slope 

 of Costa Rica. Apparently the more northern subspecies V. pulchdlus 

 verticalis Ridg. occupies eastern Costa Rica and extends southward even to 

 the Volcan de Chiriqui. I have one adult bird (the only one from the region 

 in my collection) from Boquete, Chiriqui, that is absolutely typical F. 

 pulchdlus verticalis. The characters that separate these two forms appear 

 perfectly good, and we have in these vireos another instance of a Panaman 

 form extending into western and a Central American form into eastern 

 Costa Rica. 



Stelgidopteryx. 



In the Underwood collection is an extremely interesting series of nine 

 rough-winged swallows, no two of which are quite alike. One or two 

 breeding birds from Pozo Azul and Juan Vinas, C. R., and two others in 

 fresh plumage taken in March, are rather nearer serripennis than any of 

 the other subspecies, and might almost pass for that form except that all 

 show some fulvous on the throat and one or two have dusky spots, more 

 or less well developed, on some of the longer under tail co Verts ; another 

 skin, a breeding bird, taken at Pozo A'zul, June 16, is exactly intermediate 

 between these and uropygialis ; three others from Pozo Azul and Carrillo 

 I should call uropygialis, 



I must again emphatically express my belief that there is but one species 

 of Sldgldopteryx. Since I first made this statement (Proc. New Eng. Zool. 

 Club. Vol. II, pp. 57-60, July 31, 1901), I have been accumulating what 

 specimens I could, and now have a much more extensive series, that to my 

 mind conclusively proves this. Selecting specimens of breeding birds from 

 a large amount of material I can lay out a line of skins that shows every 

 possible stage of intergradation between the various forms and every com 

 bination of characters. There is no reason for considering any of the forms 

 more than subspecies, there is absolutely no break in the chain anywhere, 

 and no gap in the breeding range of the species. 



The form Ridgway named S. salvi.ni was based on a series of intergrades 

 between serripennis and uropygialis, very unstable in character, and subject 

 to an immense amount of variation. This is the bird I called fulvipennis, 

 a name which I still do not feel at all sure is not the proper one, if such 

 intergrades are to be recognized by name at all. 



S. rldgwayi Nelson unquestionably intergrades with serripennis. I have 

 an adult male taken March 6, at Texolo, V. C., Mex., that is exactly inter 

 mediate in every character. I occasionally, also, find well developed 

 dusky markings on under tail coverts in specimens taken within the United 

 States, one adult male taken April 4, at Barrington, Ga., having these 

 markings very conspicuously developed. 



I was pleased to see that Dr. Hellmayr, in a recent paper on the birds of 

 Trinidad, agrees with me and also recognizes the very pale form of the 

 northeastern portion of South America that I named AS', ruficollis xqualis, 

 especially as other students of the American ornis have persisted in taking 

 the opposite view. 



