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83. Thalurania sirnoni Hellm. 

 Ikalurcuiia sirnoni Hellmayr, Hull. Brit. Ora. CI. six. (Oct. 10.10) p. 8. 



No. 004. S ad., 10. v. 06. " Iris, feet, and bill black."— Wing 53 ; tail 37 ; 

 bill 20$ ; caud. grad. 11 mm. Type of species. 



No. 005. S ad., 19. v. 00. "Iris, feet, and bill black."— Wing 54 ; tail 37i ; 

 bill 20 ; caud. grad. 12 mm. 



No. 070. ? ad., 20. v. 00. " Iris, feet, and bill black."— Wing 50 ; tail 32 ; 

 bill 22 mm. 



$ ad. Upper parts dark shining green, slightly tinged with bronze on the 

 occiput and upper tail-coverts. Interscapular region, when seen from in front, 

 blackish, with a hardly perceptible greenish hue. On the base of the forehead 

 a narrow edge of glittering green feathers. Chin, throat, and ear-coverts glittering 

 golden green, this colour ending in a straight line across the lower throat ; breast 

 and abdomen, as well as a large spot on the shoulder, glittering royal-purple 

 (Rido-w. viii. fig. 7). Under tail-coverts steel black, with broad white edges. 

 Lesser wiug-coverts glittering blue, remainder of the upper wing-coverts bronze 

 green ; quills purplish brown ; tail bluish black. 



The second $ ad. differs from the type by having the top of the head and the 

 npper tail-coverts much more tinged with bronze. 



? ad. Agrees with that of T. balzani Sim. in the small size and in the pale 

 greyish underparts, but has a slightly longer beak. The ? ? of '/'. jelskii Tacz. 

 and T. tsckudii are larger and have the under-surface much darker, more smoky 

 grey. 



The S of this new form, which I have dedicated to Mous. Eugene Simon, 

 of Paris, the great authority on Humming birds, resembles T. jelskii, of Central 

 Pern and Northern Bolivia, but is considerably smaller ; the green of the throat 

 is more golden, the under tail-coverts are much more broadly edged with white ; 

 the interscapular region appears blackish (not bluish green), when held against 

 the light ; and there is a narrow glittering green frontal edge, barely indicated 

 in T. jelskii. In most of these characters, as also in the small size, the new 

 form agrees with T. balzani Sim., of the plains of Eastern Bolivia, which, however, 

 is easily recognisable by its pure white under tail-coverts. 



For the present I refrain from employing trinomials for any of these 

 Thaluraniae, which, together with T. nigro/asciata, T. tsckudii, T. refulgens, 

 etc., will ultimately prove to be geographical representatives of the T. furcata 

 group, but 1 think it useful to say a few words about the distribution of those 

 forms that are found in the Upper Amazonian region. 



(1) T. nigro/asciata (Gould), which, in the S sex, is so well characterised by 

 the green of the throat being drawn to a point over the chest and separated from 

 the blue abdomen by a distinct velvety black line, inhabits the north bank of the 

 Peruvian Amazons (Iquitos, Pebas) and its northern tributaries, such as the Bio 

 Napo, Zamora, Gualaquiza, Pastaza, etc., etc. It also occurs on the Upper Bio 

 Negro (Cobati, Guia, Marabitanas, and Bio Icanna), and is not uncommonly met 

 with in the Bogota trade-collections. I have seen many specimens from Iquitos, 

 Pebas, etc., and Eastern Ecuador, and Dr. Lorenz, of Vienna, kindly sent me 

 the series obtained by Natterer on the Rio Negro, and several Bogota skins for 

 comparison. 



(2) T. tsckudii Gould, inhabits the mountainous districts of North Peru south of 



