48 Mr. D. G. Elliot on the Trochilid^. 



metallic golden green. The bill is red, tip black. This bird 

 is about the size of T. tobaci, but the tails of the two are 

 entirely different. I have compared it also with the type 

 of T. niaculicauda, and find the tail-feathers are about the 

 same width and length as the rectrices of that species ; and 

 in certain points of coloration the two resemble each other 

 more closely than any of the other members of this genus ; 

 but I do not think they belong to the same species. Should 

 the bird eventually be ascertained to be distinct, it might be 

 known as 10. Thaumatias nitidicauda. 



11. Thaumatias chionurus. 



Thaumatias chionurus, Gould, Mon. Troch. v. pi. 300 ; id. 

 Intr. Mon. Troch. 8vo ed. p. 153. 



Hab. Costa Rica. 



This pretty species, first described by Gould (/. c), is a 

 native of Costa Rica. In the colouring of the tail it differs 

 greatly from all the species of Thaumatias, so much so that 

 the term Elvira, proposed for it by M. E. Mulsant, does not 

 seem to be altogether needless. A slight difference in the 

 coloration of the sexes also separates it from the members of 

 this genus. For the present, however, I retain it among 

 the species of Thaumatias. There is no diSiculty with its 

 synonymy ; and it cannot be confounded with any of its 

 relatives. 



12. Thaumatias tephrocephalus. 



Trochilus tephrocephalus, Vieill. Nouv. Diet. Hist. Nat. 

 xxii. p. 439 (1818). 



Ornismya albiventris. Less. Hist. Nat. Ois.-Mouch. p. 209, 

 pi. 7Q. 



Thaumatias albiventris, Gould, Mon. Troch. v. pi. 301 ; 

 id. Intr. Mon. Troch. 8vo ed. p. 153. 



Hab. Brazil, Santa Catherina (Bourcier) ; Delta of the 

 Amazon (Gould). 



Mr. Gould, in his monograph, gives as a reason for adopt- 

 ing Lesson^s name of 0. albiventris for this species, that M. 

 Bourcier told him Vieillot^s type of T. tephrocephalus " was in 

 a very bad state, and the feathers of the head much w^orn 



