Ifdxon Nam.es of Certain North American Birds. 125 



to be a constant increase in size to the northern part of the 

 birds' range. 



The typical form of Catharies aura differs from the northern 

 bird in smaller size ; narrower and less well marked brown bor 

 ders to the feathers of the back (the brown border sometimes 

 entirely lacking). The color of the upper side of the shafts 

 of the primaries (brown when freshly moulted) soon bleaches to 

 an old ivory, or yellowish white. 



. Catharte* aura septentrional is differs from the typical form in 

 larger size ;< more pronounced brown borders to the feathers of 

 the upperiliurts, and the upper side of the shafts of the primaries 

 usually remain permanently dusky brown. 



The following measurements give an idea of the differences in 

 size between the two forms. 

 Catharies aura : 



Male (?), near city of Vera Cruz, Mexico. (Type of C. 

 burrovianus) . Wing, 475 ; tail, 215 ; tarsus, 62. 



Female, Southern Vera Cruz (April 7, 1901, Bangs Coll.). 



Wing, 475 ; tail, 233 ; tarsus, 63. 

 Cathartes aura septentrionalis : 



Male, Washington, D. C. (Dec. 25.) Wing, 553 ; tail, 320 ; 

 tarsus, 74.5. 



Male, Mt. Carmel, 111. (Aug. 1.) Wing, 550 ; tail, 320 ; tar 

 sus, 67. 



TANGAVIUS INVOLUCRATUS Lesson. 



In the Revue Zoologique for February, 1839, p. 41, Lesson 

 describes Tan gar ins inrolucratus from a Mexican specimen in the 

 Abeille Collection as follows : ' T. corpore nigro teneoque ; alis, 

 et cauda atrocterulescente splendent Urns ; colli phnnis, amplis, dila- 

 tate in rolucrum forma utibus. ' ' This description evidently applies 

 to a form of Callothrus, and since numerous other new birds 

 described from the Abeille Collection about the same time were 

 from eastern Mexico it is fair to infer that the present species carne 

 from the same region . Both generic and specific names appear 

 to be used for the first time in the place quoted above ; Callothrus 

 of Cassin, 1866, is thus antedated by Tangavius of Lesson, 1839, 

 and involacrat us replaces robustus for the name of the bird of 

 eastern Mexico. 



