. 916 Dr. T. A. Chapman on the Life- History 
that it is impossible to suppose that the wasps have removed 
any thing. Excepting, then, the amount of excretion in 
the form of vapour, it follows that the wasp-grubs, as well 
as Rhipiphorus and other parasites, actually feed upon an 
amount of material of only their own bulk. 
When the alimentary canal is emptied, the larva commences 
to spin its silken covering ; and now it is far from being such 
an inert larva as it has previously been: it ‘moves its head 
actively to and fro to spin the silken dome, and passes its 
head far down the side of the cell-wall, to cover it with silk. 
Further, now its last cast skin is buried. beneath the black 
deposit, it has no hold of the base of the cell by its anal seg- 
ments; and being kept from falling out by the silken covering, 
it turns on itself so as to be quite folded at its middle; an 
have frequently found such a larva completely reversed in the 
cell. Now there are two facts that prove, I think, that this 
reversal is not an accident, but the normal procedure of every 
wasp-grub :—first, that though I have found a number of 
grubs so reversed at this stage, I find none so at further ad- 
vanced stages, as would be the case were it an accident; and, 
secondly, although the silken dome and lining extends with 
any strength only for about a quarter of an inch down the 
cell, it extends almost to its base in a slighter form; and in 
the case of Vespa norvegica, Y find a strong silken lining quite 
ll. 
Rhipiphorus completes its transformations only a day or two 
after the vites 
aus. oe NEC NE Y 
oc dac cd 
Ne lt ed Tp 
