Cuap. V. HUMMING BIRDS. 93 
They poise themselves in an unsteady manner, their wings moving with 
inconceivable rapidity ; probe the flower, and then shoot off to another 
part of the tree. They do not proceed in that methodical manner which 
bees follow, taking the flowers seriatim, but skip about from one part of 
the tree to another in the most capricious way. Sometimes two males 
close with each other and- fight, mounting upwards in the struggle, as 
insects are often seen to do when similarly engaged, and then separating 
hastily and darting back to their work. Now and then they stop to rest, 
perching on leafless twigs, where they may be sometimes seen probing, 
from the places where they sit, the flowers within their reach. The 
brilliant colours with which they are adorned cannot be seen whilst they 
are fluttering about, nor can the different species be distinguished unless 
they have a deal of white hue in their plumage, such as Heliothrix 
auritus, which is wholly white underneath, although of a glittering green 

Humming-bird and Humming-bird Hawk-moth. 
colour above, and the white-tailed Florisuga mellivora. ‘There is not a 
great variety of humming-birds in the Amazons region, the number 
of species being far smaller in these uniform forest plains than in the 
diversified valleys of the Andes, under the same parallels of latitude. 
The family is divisible into two groups, contrasted in form and _ habits, 
one containing species which live entirely in the shade of the forest, and 
the other comprising those which prefer open sunny places. The forest 
species (Phaethorninz) are seldom seen at flowers, flowers being, in the 
shady places where they abide, of rare occurrence ; but they search for 
insects on leaves, threading the bushes and passing above and beneath 
each leaf with wonderful rapidity. The other group (Trochilinz) are 
not quite confined to cleared places, as they come into the forest 
wherever a tree is in blossom, and descend into sunny openings where 
flowers are to be found. But it is only where the woods are less dense 
than usual that this is the case; in the lofty forests and twilight shades 
of the lowlands and islands they are scarcely ever seen. I searched well 
