AjS'AS— chaulelasmus. 209 



Bab. Mexico, Mazatlan {Alert% Tepic {Grayson^), Valley of Mexico {Herrera% 

 Guanajuato, Guadalajara {Bughs ^). 



We have not been able to examine an example of this bird, which is also closely 

 related to A. fulmgula from Florida. Mr. Eidgway says that its small size, and, to a 

 certain extent, its narrow bill, recall the species of Querqiiedula. 



Grayson ^ shot many specimens near Tepic, but never saw one in the vicinity of 

 Mazatlan. The species doubtless breeds in the former place, as he found them there 

 during the month of June in pairs. 



CHAULELASMUS. 



Chaulelasmus, Bp. Comp. List Birds Eur. & N. Amer. p. 56 (1838) ; Gray, List Gen. Birds, p. 74 

 (1840) ; id. Gen. Birds, iii. p. 617 (1845) ; Salvad. Cat. Birds Brit. Mus. xxvii. p. 221 

 (1895). 



This genus may at once be distinguished from the true Ducks by the distinct lamellae 

 of the upper mandible, which project prominently over the lower. The chestnut 

 wing-coverts are also a feature of the Gadwalls, and the speculum is black and white 

 in both sexes,, the white patch being on the inner side. The bill is not very broad, 

 somewhat compressed, and shorter than the head. 



Two species are known — the ordinary Gadwall, C. streperus, common to the Old and 

 New Worlds, and a smaller form, C. couesi, supposed to be peculiar to the Fanning 

 group of islands in the Pacific. 



1. Chaulelasmus streperus. 



Anas strepera, Linn. Syst. Nat. i. p. 200'; Sol. & Salv. P. Z. S. 1876, p. 382'; Ferrari-Perez, Pr. 



U. S. Nat. Mus. ix. p. 173 'j Herrera, La Nat. (2) i. pp. 187', 328'; Allen, Bull. Amer. 



Mus. Nat. Hist. v. p. 32 ' ; A. O. U. Check-1. N. Amer. Birds, 2nd ed. p. 49 '. 

 Chaulelasmus streperus, Duges, La Nat. i. p. 142*; Lawr. ^lem. Bost. Soc. Nat. Hist. ii. p. 315'; 



Baird, Brewer, &Ridgw. Water-Birds N. Amer. i. p. 506'°; Salvad. Cat. Birds Brit. Mus. 



xxvii. p. 221 ". 



Pileo rufescenfci-tirunneo, saturatiore brunneo maculato ; capitis et colli lateribus fe. -ugineo tinctis et brunneo 

 minute puuctatis ; collo postico sordide brunneo ; interscapulio et scapularibus intimis nigricantibus, 

 lineis albis vel pallide fulvis angustissimis irroratis, scapularibus extemis arenario marginatis ; dorse 

 postico saturate brunneo, vix albo vermiculato, uropygio supracandalibusque velutino-nigris ; mento albido, 

 gutture brunneo, nigro maculato ; praepectore albo, nigro circulariter fasciato ; peetore et abdomine albis, 

 hoc imo fusco fasciato ; corporis lateribus, hypochondriis et crisso albis vel fulvescentibus, fusco anguste 

 fasciatis ; snbcaudalibns velutino-nigris ; subalaribus et axillaribus pure albis ; tectricibus alarum 

 minoribus brunneis, medianis castaneis; tectricibus primariorum et remigibus cinerascenti-brunneis, 

 secundariis extimis albo terminatis ; secundariis medianis externe nigris, intimis externe albis, speculum 

 nigrum et album formanribus ; rectricibus cinerascenti-brunneis, paUidiore brunneo marginatis : rostro 

 plumbeo ; pedibus sordide aurantiacis ; iride corylina. Long, tota circa 21-0, alae 11-0, caudae 4-0, culm. 1-9, 

 tarsi 1-5. (Descr. maris adulti ex Zacatecas. Mus. nostr.) 



(J inptilosi vera cestiva feminse adultsB simUis, sed saturatior. 



$ . Supra niger, fulvo marmoratus ; pUeo nigro, arenario -fulvo anguste striolato ; capita reliquo et collo 



BIOL. CENTE.-AMER., Aves, Vol. III., January 1902. 



— I 



