there is no marked difference in form between the newly-hatched young
and the adult, and in such cases we find that the young insect lives in
the same way as the adult, has the same surroundings, eats the same
food. This is the rule (see Chapters II and III) with the Apterygota,
the Orthoptera, and most of the Hemiptera. In the last-named order,
however, we find in certain families marked divergence between larva and
imago, for example in the cicads, whose larvae live underground, while
in the coccids, whose males are highly specialised and females degraded,
there succeeds to the larva--very like the young stage in allied
families--a resting instar, which in the case of the male, suggests
comparison with the pupa of a moth or beetle.

Turning to the stone-flies, dragon-flies and may-flies, whose
life-stories have been sketched in Chapter IV, we find that the early
stages are passed in water, whence before the final moult, the insects
emerge to the upper air. Except for the possession of tufted gills,
adapting them to an aquatic life, the stone-fly nymphs differ but
slightly from the adults; the grubs of the dragon-flies and may-flies,
however, are markedly different from their parents. In connection with
these comparisons, it is to be noted that the dragon-flies and may-flies
are more highly specialised insects than stone-flies, divergent
specialisation of the adult and larva is therefore well illustrated in
these groups, which nevertheless have, like the Hemiptera and
Orthoptera, visible external wing-rudiments.

From the vast array of insects that show internal wing-growth and a true
pupal stage, a few larval types were chosen for description in Chapter
VI, and a review of these suggests again the thought of increasing
divergence between larva and imago. Reference has been made previously
to the many instances in which the former has become pre-eminently the
feeding, and the latter the breeding stage in the life-cycle. It seems
impossible to avoid the conclusion that the active, armoured
campodeiform grub differing less from its parent than an eruciform larva
differs from its parent, is as a larval type more primitive than the
caterpillar or maggot. A. Lameere has indeed, while admitting the
adaptive character of insect larvae generally, argued (1899) with much
ingenuity that the eruciform or vermiform type must have been primitive
among the Endopterygota, believing that the original environment of the
larvae of th