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ART. XIV. — Monograph of the Birds composing the genera Hydropsalis, Wagler, 

 and Antrostomus, Nuttall By John Cassin. 



I. Genus Hydropsalis. Wagler, Isis, xxv. p. 1222. (1832.) 

 Fsalurus. Swainson, Cab. Cy. Birds, ii. p. 339. (1837.) 



Original description of Wagler. " Character universalis Caprimulgi ; cauda 

 profunde furcata, rectrice extima elongatissima." 



Original description of Swainson. " Gape strongly bristled. Tail excessively 

 long and very deeply forked." 



Added by me. Bill rather long, (longer than typical Caprimulgus,) slender and 

 compressed towards the tip, and having about 8 or 10 pairs of bristles, which are 

 longer than the bill and curved at their ends, gape moderate, nostrils medial, slightly 

 elevated. 



Wings long, first and second primaries generally longest, second and third strongly 

 sinuated on their outer webs, and frequently serrated on their external edges, shafts 

 of primaries very strong. 



Tail in the males usually with the two external feathers much the lono-est, 

 sometimes graduated with the two middle feathers shortest, sometimes with the two 

 middle feathers elongated and next in length to the external. 



Tarsi covered with scales and slightly feathered below the joint. Wings without 

 the white bar on the primaries which is found in typical Caprimulgus, tail more or 

 less marked longitudinally with white. 



Ohs. — This remarkable genus of American birds embraces species which admit 

 of being arranged into two groups, and which have been named by Bonaparte, 

 (Conspectus Avium, p. 58, 59,) Hijdropsales and Psaluri. The former is composed 

 of those species which have the tail simply graduated, as H. limhatus, Cassin, and 

 the latter, those having the singular form of that member in which the two central 

 feathers are next in length to the very long external feathers, as H. psalurus, Ternm. 

 (fl. torquatus, Gm.) I consider those groups as subgeneric. 



The long tail feathers in these birds vary much in length in specimens of the same 

 species, and I am inclined to think them either appendages of the plumage of the 

 breeding season, or otherwise deciduous, which Bonaparte suggests with great 

 judgment may be the case also with the central tail feathers in the Psaluri. 



All the known species inhabit South America. 



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