[Illustration: Fig. 15. (_a_) Cabbage-beetle (_Psylliodes chrysocephala_)
magnified 5 times, and its larva (_b_) magnified 12 times.]

In the larvae of the little timber-beetles and their allies (Ptinidae),
including the 'death-watches' whose tapping in old furniture is often
heard, a marked shortening of the legs and reduction in the size of the
head accompany the whitening and softening of the cuticle. This
shortening of the legs is still more marked in the larvae of the
Longhorn Beetles (Cerambycidae) burrowing in the wood of trees or felled
trunks; here the legs are reduced to small vestiges.

[Illustration: Fig. 16. _a_, Grain Weevil (_Calandra granaria_); _b_,
larva; _c_, pupa. Magnified 7 times. After Chittenden, _Yearbook U.S.
Dept. Agric._ 1894.]

Finally in the large family of the Weevils (Curculionidae, fig. 16) and
the Bark-beetles (Scolytidae), the grubs, eating underground root or
stem structures, mining in leaves or seeds, or tunnelling beneath the
bark of trees, have no legs at all, the place of these limbs being
indicated only by tiny tubercles on the thoracic segments. Such larvae
as these latter are examples of the type called _eruciform_ by A.S.
Packard (1898) who as well as other writers has laid stress on the
series of transitional steps from the campodeiform to the eruciform type
afforded by the larvae of the Coleoptera.

A fact of much importance in the transformations of beetles as pointed
out by Brauer (1869) is that in a few families, the first larval instar
is campodeiform, while the subsequent instars are eruciform. We may take
as an example of such 'hypermetamorphosis' the life-story of the Oil or