328 
TRANSFORMATIONS OF INSECTS. 
insect was the author of the destruction of the trees, for when 
a branch was carefully opened it was found to contain the living 
larvae and nymphs of the Oncideres. 
In the engraving on page 327 a beetle maybe noticed with very 
long horns upon a little twig close to the main branch. Quite 
low down the fractured end of the branch shows in the centre 
the ragged pith, but between this and the bark the tissues are 
perfectly smooth, the bark being cut through in a circular manner. 
The smoothness of the tissues has been produced by the gnawing 
of the beetle, which does not touch the pith. Within the branch, 
and on a level with the beetle, there is a larva which has made 
an excavation. A larva is also represented on the left hand side 
of the plate. Below, a nymph may be seen in a cavity, and there 
is one represented outside the branch on the right-hand side. 
Now, what is the reason that the beetle should cut away the 
branch ? If it is that which is usually considered to be true by 
naturalists, it is a most wonderful instance of superior instinct. 
It is supposed that the branch is cut off in order to prevent an 
unusual supply of sap flowing into it, or with a view of diminish- 
ing the amount of sap circulating generally in the branch. Were 
the incision not made through the bark and the flow of the sap 
not checked, the larvae would suffer from too great abundance of 
liquid in their immediate neighbourhood ; and the diminution of 
the sap is necessary for the perfection of the metamorphoses. 
The Chrysomelidce are leaf-eating insects, and attack all kinds 
of plants. Many of them are ornamented with most beautiful 
colours of gold, red, copper, bronze, metallic green, deep blue, 
azure violet, and silver, and very few of them are of a sombre 
hue. Unlike those just described, the larvae of these beetles 
generally live in the open air, fixed upon the leaves of plants 
or trees. They are stout, thick-set, and having very small legs, 
they walk but very slowly, and many of them, on account of their 
having soft integuments, protect themselves from danger in most 
interesting and curious manners. The beetles of the genus Crio- 
ceris are oblong creatures, with very narrow heads and fore-parts 
of the body, and they may be constantly seen upon the twigs 
and leaves of the beautiful white lilies which are grown in gardens. 
They may be recognised by their brilliant black colour, which is 
