246 



BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Without more specimens, however, or without further information, I 

 hesitate to give this form a new name. Bonaparte (Consp. ii. p. 110) 

 quotes '^ major f Molina" among the synonyms of A. cocoi, and further 

 remarks, — " Specimiua brasiliensia minora. Specimina ex Montevideo 

 majorat It is quite likely, although no mention is made of auy 

 differences in coloration, that Bonaparte had in view the race whose 

 distinctive characters have just been given, and that some name may 

 be found, perhaps Molina's "wcrjor", applicable to this larger, white- 

 fronted, Southern race.* 



Description of two new American Genera of Ardeid^. 

 Genus Dichromanassa, Eidgway. 



< Egretta, Bonap. Comp. List, 1838, . (Nee Bonap. 1831.) 



<^ Rerodias, Bonap. Consp. ii. 1855, 125. (Ncc Boie, 1822.) 



< Demiegretta, Baird, Birds N. Am. 1858, 662. (Nee Blyth, 1846.) 



< Florida, Boucakd, Catal. Av. 1876, 50. (Nee Baird, 1858. ) 

 <^ Ardea, AucT. (Neo Liun. 1766.) 



= Dichromanassa, Ridgw. MS. (Type Ardea rvfa Bodd.) 



Gen. ch. — Medium-sized Herons, of uniform white or plumbeous 

 plumage, with (adult) or without (young) cinnamon- colored head and 

 neck ; the form slender, the toes very short and the legs very long ; 

 the adults with the entire head and neck (except throat and foreneck) 

 covered with long, narrowly-lanceolate, compact- webbed feathers, which 

 on the occiput form an ample crest, the feathers of which are very 

 narrowly lanceolate and decurved. 



Bill much longer than the middle toe (about two-thirds the tarsus), 

 the upper and lower outlines almost precisely similar in contour, being 

 nearly parallel along the middle portion, where slightly approximated; 

 the terminal portion of both culmen and gonys gently and about equally 

 curved. Mental apex extending to a little more than one-third the dis- 

 tance from the middle of the eye to the tip of the bill, or to about even 

 with the anterior end of the nostril; malar apex about even with that 

 of the frontal feathers. Toes very short, the middle one less than half 

 the tarsus, the hallux less than half the middle toe ; bare portion of 



* Frazer (I. c.) gives an Ardea major from Southern Chile, which is, no doubt, one of 

 the races of this species; it may be well to mention, however, that the only Chilian 

 specimen I have seen resembles Buenos Ayres and Paraguayan examples, and is, 

 therefore, true cocoi. 



