these flies with their aquatic larvae recalls that of the cockroach. All
the larval and nymphal instars are active, and the wing-rudiments are
outwardly visible long before the final moult.




CHAPTER V

TRANSFORMATIONS,--OUTWARD AND INWARD


We are now in a position to study in some detail the transformation of
those insects whose life-story corresponds more or less closely with
that of the butterfly, sketched in the opening pages of this little
book. In the case of some of the insects reviewed in the last three
chapters, the may-flies and cicads for example, a marked difference
between the larva and the imago has been noticed; in others, as the
coccids, we find a resting instar before the winged condition is
assumed, suggesting the pupal stage in the butterfly's life-story.

The various insect orders whose members exhibit no marked divergence
between larva and imago (the Orthoptera for example) are often said to
undergo no transformation, to be 'Ametabola.' Those with life-stories
such as the dragon-flies' are said to undergo partial transformation,
and are termed 'Hemimetabola.' Moths, caddis-flies, beetles, two-winged
flies, saw-flies, ants, wasps, bees, and the great majority of insects,
having the same type of life-story as the butterfly, are said to undergo
complete transformation and are classed as 'Metabola' or 'Holometabola.'
Wherein lies the fundamental difference between these Holometabola on