180 MR. NEWPORT ON THE NATURAL HISTORY, ANATOMY, 
cates the purpose for which it is employed; and the habits of the Meloe larva, and its 
mode of seizing and attempting to pierce the skin of the bee that conveys it to its nest, 
confirm the conclusion deduced from the structure of its mandible. 
The gradual change of form which the mandible undergoes in the larva state, indicates 
some modification of function even during the larva period. I have already shown that the 
mandible in the adult larva is a short thickened corneous organ, more nearly resembling 
that of the perfect insect: not as in that fitted for cutting and comminuting vegetable 
tissue, nor, as in the very young, for piercing soft textures, but rather adapted for crush- 
. ing and bruising. The mode in which this organ is changed in its condition is, first, by 
deciduation, at the change of tegument, of its terminal claw-like apex, exactly as the cor- 
responding part of a true limb is thrown off at the change on the reduction of the legs to 
mere tubercles, preparatory to their future re-development in the nymph or pupa in a new 
form; next, by the growth and enlargement of every part of the structure in.a lateral, 
and its retardation in an axial direction. The result of this change is a complete obliteration 
and anchylosis, or permanent union of the whole in one powerful angulated structure, 
which retains an articulation only with its parent segment. This is the mandible of the 
adult larva. | 
Changes, similar in principle and mode of operation, but carried to a far less extent, 
take place in the other appendages of the cephalic segments of Meloé, the maxille and 
palpi, the function of which, like the structure, undergoes but little modification. 
The whole of the feeding-period of the larva state, in so far as refers to change in the 
segments of the body, is scarcely other than one of simple growth and enlargement. 
Change of form by aggregative development, as we have seen, commences in the append- 
ages and parts of the head; but the tegument of the segments in the larva still retains 
its original flexible uniform condition, and is scarcely thrown into folds, even at the junc- 
tion of separate segments. The nuclei of its component cells continue to reproduce, and 
when the external layer becomes aged and resistant, obstructing the function of the in- 
ternal, it ceases to be nourished and is removed. But as the entire body advances to its 
maximum of size, certain forces become active in its internal structures, which lead to those 
rapid and important changes of form in the whole which we recognise as the Metamor- 
phoses of the Insect. | 
Those structures which are the immediate agents of all voluntary and instinctive move- 
ments, the muscles, are also those of the Metamorphoses. Nourished to the utmost while 
he ng hep ihe una in gue ya so 
from it, and having their ee a. I "Ba 5 we Mero» 
form of the portion they are aida Bs RR ete 
extent in proportion to = degree of its ae en ee — = 
off MU intolee:dnsigea ‚and to the number and direction 
pose y conn Ao ln wd iege which first excites these structures into 
not, as there seems reason to apat dd i e reichen m ——— «n 
chsage; ob feds Arial dos = ed to an accumulation, and subsequent dis- 
uring growth in the structures themselves, a vital endowment of 
