376 CTPSELID^. 



paUidior, abdomine quam guttur paulo obsouriore. Long, tota circa 4-0, alae 4-5, caudse 1-55. (Descr. 

 maris ex Mexico. Mus. nostr.) 



Hah. NoETH America, Western States from British Columbia southwards s.— Mexico 

 {de Saussure), Sierra de Mexico (Bebouch), Kio Seco near Cordova, Valley of 

 Mexico 7 {Sumichrast), Puebla {Mus. Brit.^% Laguna del Eosario in Tlaxcala 

 {F. Ferrari-Perez^), Guichicovi^ Tehuantepec {Sumichrast, in U. S. Nat. Mus.^) ; 

 Guatemala, Raxche^, Coban ", Duenas, Alotenango and Tierra Caliente generally 

 {0. S.&F. JD. G.) ; Honduras {Byson, in Mus. Brit. ") ; Nicaragua, Eio Escondido 

 {C. W. Bichmond, in U. S. Nat. Mus.) ; Costa Rica (Van Patten, in V. S. Nat. Mus.). 



This species is a near ally of C. pelagica, but may be distinguished by its smaller 

 size, the wing being on an average nearly an inch shorter ; the tarsi and toes, however, 

 are relatively longer ; in colour it is generally paler. 



a vauxi was discovered by Townsend in the Columbia river, where he found it 

 common, breeding in the hollow trunks of trees, in the same manner as C. pelagica., and 

 laying four white eggs i. The bird is now known to be widely spread in Western North 

 America from Puget's Sound to California. It occurs also in Mexico and Guatemala, 

 and thence southwards to Costa Rica. In Guatemala we used to see it not unfrequently 

 in the winter months flying over the open ground between the volcanoes of Agua and 

 Fuego, and occasionally a -flock would fly low enough to enable us to secure a few 

 specimens. We also observed it in various parts of the department of Vera Paz. 

 Though there can hardly be a doubt that these southern birds are simply individuals 

 of C. vauxi in their winter-quarters, some attempts have been made to separate them 

 as distinct. Thus Mr. Lawrence at one time referred a Duenas specimen to his 

 C. gaumeri, and associated with it an example from Tehuantepec, and these birds he 

 seems afterwards to have discriminated under the name of C. similis *. When due 

 allowance is made for small individual differences in size, and for the wear and tear of 

 the plumage, we do not think it possible to deflne these southern birds as distinct from 

 the true C. vauxi. 



5. Chaetura gamneri. 



Chtetura vauxi, Lawr. (nee Townsend) Ann. Lye. N. Y. ix. p. 304 \ 



Ckatura gaumeri, Lawr. Ann. N. Y. Ac. Sc. ii. p. 245 " ; Boucard, P. Z. S. 1883, p. 451 ' ; Eidgw. 



Pr. U. S. Nat. Mus. vi. p. 415*; Salv. Ibis, 1889, p. 367"; Stone, Pr. Ac. Phil. 1890, 



p. 206 " ; Hartert, Cat. Birds Brit. Mus. xvi. p. 482 '. 

 Chmtura yucatanica, Lawr. Ann. N. Y. Ac. Sc. ill. p. 156 ". 

 hatura peregrinator, Lawr. Ann. N. Y. Ae. Sc. iii. p. 273°. 



C. vaucci similis, sed plerumque minor supra saturatior, abdomine et tectricibus subcaudalibus quoque obscu- 

 rioribus. Loug. tota circa 4-0, alae 4-2, caudse 1-4. (Descr. maris ex Cozumel I., Yucatan. Mus. nostr.) 



* Probably the same bird is referred to by Mr. Eidgway as C affinis (Pr. U. S. Nat. Mus. ix. p. 158). We 

 have not been able to find any description of it or of C. similis. 



