52 ON THE CLASSIPIOATiON OF BIRDS. 
birds consisted both of honey and of minute insects. 
Since then some modern writers have flown to the other 
extreme, and, wholly unsupported by facts, have declared 
their belief that these birds live entirely upon insects. 
In this they are as much mistaken as in their former 
assertion; the fact being, that they feed indiscriminately 
upon both. The two filaments, which were supposed 
to be tubular, are perfectly flat, and very tliin, — a structure 
obviously adapted for licking up the food. We have 
reason, also, to believe that these processes are covered 
with a mucilaginous substance, sufficiently adhesive to 
act upon the pollen of flowers, and the wings of the 
small dipterous insects, w'hich the humming birds chiefly 
select for their animal diet. The tongue of the African 
sunbirds ( Cinnyrid/e) we have never had the opportunity 
of examining ; but by a fortunate chance we have <lis- 
covered that the type among the Australian honeysuckers 
(^Meliphagida:), which represents the TruchiUdce, has the 
tongue constructed precisely the same as those birds. 
This brings us to the second description of extensible, or 
rather of suctorial tongues, and which is of a form almost 
peculiar to the honeysuckers of Australia, and its islands. 
In these birds the tongue is not nearly so extensible as in 
the Trochilidee, being seldom more than half as long again 
as the bin ; nor are the bones of tlie os hyoides carried 
back upon the skull, as in the woodpeckers and humming 
birds. Nevertheless, the structure appears especially 
adapted for suction : the form of the Imver part is the 
same as in ordinary birds; but the end is composed of a 
great number of delicate fibres or filaments, exactly re- 
sembling a painter’s brush. Lewin^ who drew and de- 
scribed these birds in their native region, has figured the 
tongue of the warty-faced honeysucker* {Meliphaga 
phrygia), and describes the bird as sometimes to be 
seen “ in great numbers, constantly flying from tree to 
tree (particularly the blue gum), feeding among the 
blossoms, by extracting the honey with their long tongues 
* Birds of New Hollandj pi. 4 . 
