98 Bulletin of the Brooklyn Entomological Society Vol. XIV 
etc., or even to the pedogenesis of certain Diptera. While such 
an explanation may be quite valid, it does not alter the fact that 
in some Homoptera (male Coccide) a complete metamorphosis 
may occur, while in other Homoptera (in which the females as- 
sume the adult form as well as the males) such a complete meta- 
morphosis does not exist—so that in such cases, at any rate, com- 
plete metamorphosis may or may not occur within the same order 
of insects, and is therefore not always to be taken as a criterion 
for determining the interrelationship between orders, since it does 
not hold good even within the same order of insects. 
The older entomologist, particularly the English school of in- 
vestigators who followed Ray, Leach and others, laid great 
stress upon the type of metamorphosis exhibited by insects, in 
grouping the orders together ; while the earlier French entomolo- 
gists, being influenced by Cuvier and other antomists, gave greater 
weight to comparative morphology in grouping the orders to- 
gether. Later investigators attempted to combine the two sys- 
tems; but with the exception of the German embryologists such 
as Korschelt and Heider, Heymons and others, the tendency 
among recent investigators has been to place great weight upon 
the comparative anatomy of the adult insects, since the adults 
represent the important stages in the evolutionary process, to 
which are intrusted the propagation of the race and the continu- 
ance of the species, and represent the perfected types toward 
which evolution is evidently tending. The larval stages, on the 
other hand, are regarded by some recent investigators, largely as 
later-developed “interpolated” adaptive stages, frequently pro- 
vided with provisorial structure, etc., having no particular phylo- 
genetic significance ; and indications of interrelationships offered 
by larval or immature forms are frequently ignored in recent 
works, largely through the fact that systematists have centered 
their attention upon the adult stages, which usually offer easier- 
used identification characters, are more readily handled, and 
which are easier to collect and preserve. I think, however, that 
larve (and immature forms) when compared together may offer 
some very valuable clues to the interrelationships of the insectan 
orders, and while the comparative morphology of adult forms 
offers one of the most reliable means of determining such inter- 
