124 The Bird 
of a bird, mention was made of the two long bones which 
branched out from the rear of the tongue and which are 
all that remain of the third ancestral gill-arch. In the 
Flicker, the slender, white tongue divides into these two 
branches just in front of the glottis and from here they 
extend backward, passing one on each side of the wind- 
pipe, and on upward, following the curve of the skull, 
then forward, lying together upon the forehead. Not 
even here do they end, however, but actually reach some 
distance into one nostril! So when this bird stretches 
out its tongue, the tips of the rear branches leave the 
opening of the nose and shoot around over the surface 
of the skull until they have gone as far as possible. No 
wonder the poor ants have but little chance when a 
Flicker visits their hill and sets the marvellous mechanism 
of his tongue rapidly to work. And no wonder the 
enthusiasm of an ornithologist never fails, when he thinks 
of the scores of similarly interesting structures still await- 
ing investigation. 
The tip of the tongue in the sap-sucking woodpeckers 
is beset with numerous hairs forming a brush-like instru- 
ment, but spines take the place of hairs in the species 
which feed exclusively on insects. It is known that the 
exact proportion of insects in the diet of any particular 
kind of woodpecker is reflected in the more or less per- 
fect. adaptation of the minute structure of its tongue to 
that end. 
In the sapsuckers, too, the tongue is comparatively 
short, doubtless because the sap flows readily from the 
holes which these birds bore. Hence they require no 
