Mr. D. G. Elliot on the Trochilidse. 47 



9. Thaumatias nigricauda^ sp. nov. 



Top of head dull green ; nape and back shining grass-green. 

 Throat and upper part of breast bright metallic grass-green ; 

 flanks dark purplish brown^ each feather tipped with metallic 

 grass green ; but the general appearance of the flanks is much 

 duller and darker than the breast^ which lies above them like 

 a shield. Centre of abdomen^ thighs, and under tail-coverts 

 pure white. Upper tail-coverts like the back, but with a 

 purple tinge. Tail has the two median rectrices black, with 

 a very slight tinge of green in some lights, remainder blue- 

 black, edged with white on their tips. Wings purple. Bill — 

 maxilla black, mandible flesh-colour, tip black. Total length 

 3^ inches, wing 2, tail 1^, bill f . 



Hab. Trinidad, British Guiana ( FerreaM<2?) j Cayenne (Fer- 

 reaux) ; Bahia {Berlepsch) . 



There is a Humming-bird from Cayenne which bears some 

 resemblance to the T. tephrocephalus, but is smaller and more 

 delicately shaped, has a difi'erently coloured tail and white 

 under tail- coverts. I have seen a fair number of specimens 

 all resembling each other ; and although I cannot place them 

 satisfactorily with any of the described species of Thaumatias, 

 yet I hardly feel myself authorized to definitely give them a 

 new name with only my present materials to judge from. I 

 will point out the differences perceived by me, which per- 

 haps may assist some ornithologist with a good series of 

 specimens at his command to determine the proper place the 

 bird should occupy. The breast and throat are a more golden 

 green than that part of T. tephrocephalus ; but the chief cha- 

 racters which seem to separate them are the colour of the 

 under tail-coverts and shape and colour of the rectrices. In 

 the Cayenne bird the tail-feathers are narrow and slender, 

 the median pair are golden green for their entire length, the 

 remaining feathers have the entire inner webs, except the 

 tips, black; the outer webs are metallic golden green, this 

 hue not extending the entire length of the web on the outer- 

 most feather, which is black on both webs below the tip. 

 All the lateral rectrices are conspicuously tipped with bright 



