xxxviii INTRODUCTION. 



nearly allied. It will be seen^ on reference to my account of G. hirsuta, that when it was written I was much per- 

 plexed with regard to its synonymy, or, rather, as to whether the small red-coloured bird, G. Mazeppa, was or was 

 not identical with it ; and although some years have since elapsed, I have not even now been able to arrive at a 

 satisfactory solution of the difficulty. Under these circumstances, I think it will be best to regard the G. Mazeppa 

 as distinct ; and this view of the subject is supported by the fact that I do not find small red-coloured bii'ds accom- 

 panying the allied species, G. affinis, Lawr., which is a native of Bogota. I think it likely that all these birds, when 

 fully adult, have the tail shorter and more rounded than during the period of immaturity or at the end of the first 

 year of their existence. The youthful state, then, is indicated by a more cuneate form of tail, all the feathers of 

 which are pointed and tipped with white ; and as the birds advance in age, at each moult the tail-feathers become 

 more rounded and the w^hite tipping less, until at length it is reduced to a mere fringe, existing in some instances 

 on the middle feathers alone. 



The distribution of the species of the genus Glaucis extends over the whole of the eastern parts of Brazil, the 

 Guianas, Trinidad, Tobago, Venezuela, the banks of the Amazon, New Granada, and Veragua. 



5. Glaucis hirsuta ............... Vol. I. PL 5. 



TrocUlus DominicuSy Licht. Dubl. p. 12 ; Cab. Schomb. Reise Guian. torn. iii. p. 708. 



ferrugineus, Wied, Beitr. iv. p. 20. 



stiperciliosuSyfcem., Less. Hist. Nat. des Col. p. 38, pi. 7 ; Id. Traite d'Orn. p. 289 ; Jard. Nat. Lib. 



Humming-Birds, vol. ii. p. 120, pi. 27 ; Burm. Th. Bras. torn. ii. p. 324. 



hirsutus, Cab. et Hein. Mus. Hein. Theiliii. p. 4. 



Habitat. Eastern Brazil, Venezuela, and the Island of Trinidad. 



6. Glaucis Mazeppa Vol. I. PL 6. 



Habitat. Cayenne, the Guianas, and the Islands of Trinidad and Tobago, 



7. Glaucis affinis, Lawr. ............. Vol. I. PI. 7. 



Habitat. The high lands of New Granada. Specimens are frequently sent from Bogota. 



8. Glaucis lanceolata, Gould ............ Vol. I. PI. 8. 



Habitat. Para. 



9. Glaucis melanura, Gould ............. Vol. I. PL 9. 



Habitat. The banks of the Rio Napo and the Rio Negro. 



10. Glaucis Dohrni •••••........ Vol I PI 10 



Glaucis Dohrni, Cab. et. Hein. Mus. Hein. Theil iii. p. 4. 

 Habitat. Southern Brazil. 



M. Bourcier has given Ecuador as the locality where his specimen was procured ; but my bird was received 

 direct from the district of Espiritu Santo in Brazil. 



11. Glaucis Ruckeri ............. Vol I PI 11 



Threnetes Ruckeri, Reichenb. Aufz. der Col. p. 1 5 ; Id. Troch. Enum. p. 12. 

 Glaucis Ruckeri, Cab. et Hein. Mus. Hein. Theil iii. p. 4. 

 Habitat. Veragua. 



12. Glaucis Fraseri, Gould ............. Vol I PI 12 



Mr. Eraser collected at Babahoyo, in Ecuador, specimens of a bird which both Dr. Sclater and myself con- 

 sidered to be identical with the Glaucis Ruckeri, but in which, on a more minute comparison with specimens from 

 Veragua, I find such differential characters as to entitle it to a distinctive position ; I have therefore named it after 

 its discoverer, as a just tribute to one who has played a good part in the furtherance of science. The G. Fraseri 

 differs from G. Ruckeri in being rather larger in size, in having a smaller amount of rusty red on the chest, and in 

 having a decidedly grey breast ; in other respects the two birds are very similar. 



The following is Mr. Eraser's note respecting this species :— 



