208 Mr. A. Murray on the History of 
which the Rhipiphori are ids be found that the lid of the ji 
has r a thin spot, or other defect, in the middle : 
is not always shareable,” nor perhaps even in the made 
of instances; but still it is so very often, and I believe the 
lid in the Rhipiphorized cells is never so strong as in the 
others. The explanation of it seems to be, that the RAipi- 
phorus-grub attacks the ie ch ub before it has completed 
its lid, and does it sufficient in to prevent its properly 
finishing it. Where the lid has eon finished at all, the egg 
has probably been laid just before the grub began to spin 
up; where it is unfinished, it may have been laid a day or 
two before. 
This imperfection of the lid is of essential advantage to the 
Fihipiphorus afterwards. I think in one of my former papers 
I drew attention to the fact that the perfect insect made its 
way out of the cell in quite a different fashion from the per- 
fect wasp. The wasp cuts its way out through the parch- 
ment-like lid with its strong mandibles; but the mandibles of 
the perfect Rhipiphorus are small, we ak, and inadequate to 
the purpose, and it never uses them ; it bursts its way through 
by main force, pushing the crown of its head against the lid 
until it gives way. A bos lid ir of normal strength, the 
Rhipiphorus might never get out, but die entombed in the 
chest in which it had Dei ine allowed itself to be locked ; 
and the lid would be of normal strength if the egg of the 
Rhipiphorus were not soon hatched and the wasp-grub at- 
tacked before the lid is completed. Possibly the increased 
heat caused by the ie the cell may start the egg more ra- 
vidly than would otherwise have been the case, so that it 
will be hatched as soon as every thing is ready for it. It is 
an instance of adaptation of mode of life to subsequent require-. 
ments, which looks very analogous to adaptation of structure 
to urpose, 
sometimes to the other, but, so far as I have oes the hea 
always over or to the shoulder (baby-fashion), and the tail 
to the tail (see fi 
The effect of this, , I may observe in passing, is to k 
the grub with its head towards the mouth of the cell, a posi- 
tion it could not have obtained had it commenced its repast 
with its head to the tail instead of to the shoulder. This at- 
