‘160 NATURAL HISTORY OF WASPS. 
bage caterpillars, changes, in a few minutes, into 
a bundle of little yellow cocoons. We need not 
attribute any great sagacity to the ichneumon grubs, 
They probably eat the fatty matter, merely because 
their instinct prefers it, because, in fact, they like it 
best. They do not touch the “host’s” structures till, 
when she ceases to make fat, there is nothing else to 
eat, and then, and not till then, they leave her. 
The larvee of the wasps, with which we have here 
to do, are generally exempt from this particular 
danger of childhood. Not that wasps and bees, 
which, with the kindred ichneumons, constitute by 
far the larger proportion of these parasites, spare 
their own species, but at least our British Vespidee 
are pretty free from such attacks. 
The use of the fat masses in wasps is such as has 
been described; they are future food for the insect. 
In the honey-bee they serve another purpose, as it is 
from these that the wax is formed; and accordingly 
they are accumulated in the greatest abundance in 
the immediate neighbourhood of the ventral scales, 
just behind the external wax-pockets. The ventral 
scales of the wasp have little beyond their external 
marking, to distinguish them from the dorsal, but in 
the honey-bee there is a great difference between the 
scales in these two situations. Thus, the ventral 
scales of the honey-bee are wide, and thick, and 
clothed with branched hairs at the free edges. They 
have a strong horny line running down the middle, 
on either side of which is a thin, seemingly struc- 
tureless, horny membrane. As the wax plates are of 
the form and size of this membrane, and of a lami- 
nated structure with the cleavage parallel to the 
