440 Supplement to the A. 0. U. Check-List. I July 



The present supplement is made up almost wholly of purely 

 nomenclatural changes and represents a considerable portion of 

 such cases now pending. The number of additions and changes 

 here treated is 32; of rejections, 35. 



I Witmer Stone, Chairman 

 J Harry C. Oberholser, Secretary 

 Committee \ Jonathan Dwight 

 T. S. Palmer 

 [ Charles W. Richmond 



ADDITIONS AND CHANGES OF NOMENCLATURE. 



Megalestris Bonaparte becomes Catharacta Brunnich (Ornith. Boreal., 

 1764, p. 32), because the latter has for its type, by subsequent desig- 

 nation of Reichenbach 1851, Catharacta skua Brunnich, and, further- 

 more, is not preoccupied by Catarractes Brisson, a word of different 

 classical ending. (Cf. Mathews, Novit. Zool., XVII, No. 3, Dec. 15, 

 1910, p. 498; Oberholser, 'The Auk,' XXXVI, No. 3, July, 1919, 

 p. 418.) The only North American species is 

 35. Catharacta skua Brunnich. 



Subgenus Thalasseus Boie becomes Hydroprogne Kaup (Skiz. Entw.- 

 Gesch. Nat. Syst. Eur. Thierw., 1829, p. 91; type by subsequent 

 designation [Gray, Genera Birds, III, 1846, p. 658], Sterna caspia 

 Pallas), because the type of Thalasseus is Sterna sandvicensis Lath- 

 am, and Hydroprogne Kaup is the earliest available name for the 

 present group. (Cf. Mathews, Novit. Zool., XVII, No. 3, Dec. 15, 

 1910, pp. 497-498.) 



Subgenus Actochelidon Kaup becomes Thalasseus Boie, because the 

 type of Thalasseus proves to be, by designation of Gray (List Gen. 

 Birds, 1840, p. 79) (cf. Stone, Science, N. S., XXVI, No. 666, Oct, 4, 

 1907, p. 445; Mathews, Novit. Zool., XVII, No. 3, Dec. 15, 1910, 

 pp. 497-498), Sterna cantiaca Gmelin ( = Sterna sandvicensis Lath- 

 am), which designation the previous action of Kaup in proposing 

 Actochelidon with the same species as type does not nullify. 



Hydrochelidon Boie becomes Chlidonias Rafinesque (Kentucky Ga- 

 zette, I, No. 8, Feb. 21, 1822, p. 3, col. 5; type by monotopy, Chlidonias 

 melanops Rafinesque ( = Sterna surinamensis Gmelin) (cf. Rhoads, 

 'The Auk,' XXIX, No. 2, April, 1912, pp. 197-198), because the 

 latter name has priority. The North American forms of this genus 

 are: 



77. Chlidonias nigra surinamensis (Gmelin). 



78. Chlidonias leucoptera leucoptera (Temminck). 



