210 Mr. A. Murray on the History of 
in which, under the rk ea are to be distingwieha? a pair 
of wasp- -grub's m andibles. s the unconsumed part of the 
skin, and denies what Mr. St tone saw, instead of the exuvie 
of torpes tenants adhering to the tail as I had supposed. 
I do not think the above facts are explicable on any other 
view me ten I have above stated; and it removes or explains 
many other difficulties which I last year thought unsurmount- 
able. On looking back at the arguments I ‘then used, they 
still seem to me, for the most part, sound, all but the premises. 
These unhappily have the slight defect of being erroneous. 
started by assuming that where two eggs were found in a 
wasp’s cell, one of them must belong to the wasp, the other to 
the Ehipiphorus ; and I reasoned out its life-history as a ne- 
cessity from that ; and were that so, I still think it was a 
necessary course of li fe. But I now see that the two eggs have 
nothing to do with the Rhipiphorus; they are both wasp’s (a 
mere instance of misplaced zeal on the part of the wasp- 
mother), of which one is hatched, the other dies. No double 
tenancy, I venture to say, ever occurs except when a Rhi- 
ptphorus m present. The en ok a reversed grub to 
which I drew attention in t paper, which I then 
thought might be connected 24 yo 7, does not now, 
with our fresh information, seem to belong to it. Its ex- 
planation is still to seek; but of the other facts, the only 
one which seems to require explanation is how the Rhipipho- 
TUS- can grow as big as a wasp upon no more food than 
the body of a single wasp-grub. The explanation seems 
be this. The wasp-grub has already assimilated all nu ds is 
necessary to iib. a body of the bulk of a Rhipiphorus. The 
materials needed by both are the same. AH that is wanted, 
then, is that the Rhdpiphorus should build up its frame of the 
matter already assimilated by the wasp; in other words, it 
transfers the assimilated matter into a new shape, and no 
more, It is an extreme instance of what we know in our own 
e require a vastly greater amount of vegetable matter 
for food than animal matter, and simply because the latter 
is, in a great measure, ready assimilated to our hand. It 
must be the same principle carried to its extreme that enables 
the Rhipiphorus-grub to do so much upon so little: and in 
E roof of this I may note that it makes almost no excretions ; à 
ittle, very Ly scrap of yellowish-brown jelly, scarcely larger 
then two pins’ heads, resting. on the a rd is all that has 
dropped tig it in the whole course of its 
. The fact that the EAipiphori which come em of the queens' 
cells are (like the queen wasps) larger than the other Rhipt- 
phori, but indifferently male and female, is doubtless an- 
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