Messrs. Salvin and Elliot on the Trochilidae. 269 



merely returning occasionally to see that they are safe, and 

 to take care of the young birds as soon as they are hatched. 

 The colour of the eggs so much resembles the material in 

 which they are laid that it is difficult to distinguish them from 

 it without careful search. 



" After heavy rain the Wire-bird may be seen frequenting 

 and running along the edges of the pools of water ; but gene- 

 rally it finds little water in the island to indulge its wading 

 propensities. This deprivation does not appear, however, to 

 interfere with its happiness ; for it is very doubtful if it ever 

 leaves the island." 



There seems to be no appreciable difference in the colour 

 of the sexes. The young remain to be described. 



XXXI. — Notes on the Trochilidse. The Genera Pygmornis, 

 Glaucis, and Threnetes. By Osbert Salvin, M.A. &c, 

 and D. G. Elliot, F.L.S., F.Z.S., &c. 



[Continued from page 14.] 



II. The Genus Pygmornis. 



The species of this intricate group can be differentiated only 

 by a close study of the changes which take place in the plumage 

 exhibited by individuals, both as regards their sex and age. 

 Mr. Gould, in his article on Phaethornis adolphi (Mon. i. 

 p. 85), records M. Salle's observations as regards the rela- 

 tionship between the colours of the sexes of this species as 

 ascertained by him from actual dissection of specimens pro- 

 cured near Cordova, Mexico. His conclusions were, that all 

 the individuals with short and rounded tails were males, 

 while the females had the two central rectrices more pro- 

 longed, and the lateral with a dark zone between their bronzy 

 bases and buff tips. Viewing the other members of the group 

 with the light that these observations give us, we find that 

 the males as they increase in age grow darker on their under 

 surface, especially on the throat, that the tails in the same 

 sex become shorter and more rounded, and that the light colour 

 of the tips becomes evanescent — a similar fact to that which 



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