the primitive form of the Decapoda, have most truly preserved their
original mode of development. Now, the majority of the Orthoptera quit
the egg in a form which is distinguished from that of the adult Insect
almost solely by the want of wings; these larvae then soon acquire
rudiments of wings, which appear more strongly developed after every
moult. Even this perfectly gradual transition from the youngest larva to
the sexually mature Insect, preserves in a far higher degree the picture
of an original mode of development, than does the so-called complete
metamorphosis of the Coleoptera, Lepidoptera, or Diptera, with its
abruptly separated larva-, pupa- and imago-states.

The most ancient Insects would probably have most resembled these
wingless larvae of the existing Orthoptera. The circumstance that there
are still numerous wingless species among the Orthoptera, and that some
of these (Blattidae) are so like certain Crustacea (Isopods) in habit
that both are indicated by the same name ("Baratta") by the people in
this country, can scarcely be regarded as of any importance.

The contrary supposition that the oldest Insects possessed a "complete
metamorphosis," and that the "incomplete metamorphosis" of the
Orthoptera and Hemiptera is only of later origin, is met by serious
difficulties. If all the classes of Arthropoda (Crustacea, Insecta,
Myriopoda and Arachnida) are indeed all branches of a common stem (and
of this there can scarcely be a doubt), it is evident that the
water-inhabiting and water-breathing Crustacea must be regarded as the
original stem from which the other terrestrial classes, with their
tracheal respiration, have branched off. But nowhere among the Crustacea
is there a mode of development comparable to the "complete
metamorphosis" of the Insecta, nowhere among the young or adult
Crustacea are there forms which might resemble the maggots of the