DESCRIPTION OF TWO SUPPOSED NEW SPECIES OF SWIFTS. 



r.v 



RoilEKl' RiDGWAV. 

 Ciirtitiiv (if Ihv I>i jxirlninil of /iirds. 



Chaetura la-wrencei, sp. uov. 



Sp. Ch A"R. : Similar to C. (/uianeims Ilartert, bat smaller, longer ni)per 

 tail-coverts darker (outer web almost wholly glossy blackish), and 

 flanks paler slate-gray, in marked contrast witli the glossy black under 

 tail-coverts. Wing, 3.85-4.20; tail (to base of spines), 1.35-1.45. 



Habitat: Grenada, West Indies; also, Tobago, and Trinidad, or 

 Venezuela? 



Type, iS^o. 84841, XJ. S. National Mus(Mim, 9 adult, Grenada, May 7, 

 1881; J. G. Wells. (Length, 4^- inches, extent of wings, 10 inches.) 



An example in the collection of Messrs. Salvin and Godman, of un- 

 certain locality (labeled "Venezuela?") is quite identical with the 

 type in coloration, but is considerably siualler, the length of the wing 

 and tail being the mininuini of those given above. It is labeled " Chce- 

 tura salrini Hartert" (uiii)ublislied synonym of G. (/uianensis Ilartert); 

 but, having a typical .specimen of the latter for comparison, from 

 British Guiana, and also five good specimens from Costa Ilica and 

 Nicaragua, I feel quite certain it is different, all of the six specimens 

 of C. [/2(i<tnrnsi.s\vciYuVfi wholly gray upper tail-coverts and much darker 

 flanks, the dark gray color of the breast gradually shading into the 

 glossy black of the under tail-coverts. 



The two forms arc closely allied to ('. c'mereiventris Scl., of Brazil, 

 and the three should i)robablybe considered geographical races of one 

 species rather than distinct s[)ecies, a more exact idea of their relation- 

 ship being expressed by the following nomenclature: 



1. Chwiura cinereiiienfyi.s Scl. lU'azil. 



2. Chcvtiira cinereiventriti gulanensis (Hartert). Guiaiui to Nicaragua. 



3. Chwtiira cinereiventris laivrencei Ridgw. Grenada; also, Tobago, 

 Trinidad, or Venezuela? 



The three forms maybe distinguished by the following characters: 



o'. B<'Ily and llauks light gray, liko breast, abruptly contiaisted with glossy Wack of 



iinder tail-coverts. 



?>'. Upper tail-coverts black, or with ouly iuuer webs edged witli gray; rump, 



lighter gray; larger (wing 4.20-4.30). Hab., Brazil C. ciitertiventris. 



Proceedings Kutioiial Miiseiiin, Vol. XVl — Ko. 923. 



43 



