46 
Psyche 
[March 
carnivorous species where the colony is consistently smaller. 
Here individual size does not respond to abundant food 
supply, but instead an increase in the number of individuals 
or in the size of the colony occurs. This condition appears 
to be repeated very generally in other, non-social, groups 
of insects, although increase in numbers is not so patent in 
the case of non-gregarious species. It must be said, how- 
ever, that the bulkiest of all insects like the goliath beetles, 
hercules beetles, certain phasmids, saltatorial Orthoptera, 
giant silk-worms and the like are vegetarian, although the 
dragon-flies, tarantula-killer wasps and mantids of carni- 
verous habits attain exceptionally large size. Also, the 
largest insects which, so far as we know, ever existed were 
predatory dragon-flies. It may be said as a rule that the 
smallest insects as well are vegetarian, saprophagous or 
microphagous although there are many minute entomopha- 
gous parasites. Predatory or carnivorous forms are neither 
abundantly represented among the smallest forms of insect 
life, nor are they conspicuously numerous among the 
largest. 
Abnormalities in size among certain individuals may 
occur through a gross insufficiency of food during growth. 
Certain of the larger muscoid flies that develop in ferment- 
ing or decaying materials may vary considerably in size, 
frequently producing some greatly dwarfed individuals 
where their food supply has failed before larval growth was 
completed. Such specimens develop completely except for 
size. The partly grown larvse of certain dermestid beetles 
may even decrease in size when starved and again grow to 
produce normally sized individuals when food is restored. 
Such abnormalities do not of course apply to our present 
discussion. 
Certainly no generalizations concerning size in insects 
can be derived from the conflicting mass of details which 
present themselves when we attempt to correlate size with 
any of the foregoing trophic, developmental or environ- 
mental differences. Nevertheless, the size range in a great 
many taxonomic groups is very restricted; in others size 
varies widely, and occasionally giant forms appear singly 
or sporadically in groups otherwise very homogeneous in 
