44 OUR BIRD ALLIES. 
leaping up to them again and again, as though to 
suck the milk from their udders. The true object 
of its presence, however, may be traced to the insects 
which invariably torment cattle alike by night and by 
day, and which fall victims in their thousands to its 
voracious appetite. And it may be noticed that the 
animals themselves in no wise object to its presence, 
seeming, indeed, to be acquainted with its good 
offices, and to welcome rather than to dread its arrival. 
Still more serviceable is the nightjar in devouring 
cockchafers and June-bugs, which it destroys literally 
by thousands before they are able to lay their eggs 
and provide for a future generation. Now a cock- 
chafer, before it becomes a perfect beetle, passes no 
less than three years as a grub beneath the surface 
of the ground, feeding upon the roots of various 
crops, and destroying even more than it actually 
devours. And the damage which these grubs cause 
is almost incredible. Large fields of produce are 
utterly destroyed by their incessant attacks, and, as 
they live entirely concealed from view, it is practi- 
cally impossible to destroy them until they emerge 
from the ground as perfect beetles. 
Nor when their life as grubs is at an end are they 
impotent for further mischief, for the perfect cock- 
chafer is as destructive to foliage as its larva is to 
roots, and frequently even in this country, and com- 
monly upon the Continent, strips entire trees of their 
leaves, and injures them severely, of course, in so 
doing. A bird, therefore, which preys principally upon 
these beetles, and destroys them by myriads before 
