48 
Psyche 
[March 
paratively “giant” generic type (Pelecinus, Leptofoenus and 
Ibalia, respectively) in each superfamily. This is true not- 
withstanding the fact that certain of the minute parasitic 
forms have developed the most unexpected method of 
development, known as germinogony, whereby a single egg 
produces enough larvae to consume a large caterpillar. Here 
numbers replace size in exploiting the trophic field. On the 
other hand in the same order Hymenoptera other super- 
families do not show such constant size. The Tenthredinoi- 
dea, Ichneumonoidea, Vespoidea and Formicoidea include 
moderate-sized species with numerous small and scattered 
large types, showing that a wide variation in size in this 
extensive order is characteristic only of certain groups. 
The largest known Hymenoptera are Jurassic Siricoidea, a 
superfamily whose living representatives are still char- 
acteristically large insects with a few small, derived types. 
Another very extensive order, the Lepidoptera, show 
more or less similar conditions with reference to size. This 
group was at one time rather crudely divided into “Micro- 
lepidoptera” and “Macrolepidoptera.” The former group is 
really composed almost entirely of one superfamily, the 
Tineoidea with a slight admixture of more primitive forms 
(Micropterygoidea) that are really quite closely similar to 
certain much larger ones (Hepialoidea) near which they 
are now placed. The more rational taxonomic grouping of 
these primitive types into two superfamilies corresponds 
closely to the size of the included types. 
With these facts in mind we must discard at once any 
supposition that relates body size in insects to fortuitous 
circumstances or to adaptations readily acquired in relation 
to a changing or specialized type of environment. Size ap- 
pears as a highly stable character, deeply imbedded in the 
genetic constitution of at least most groups of insects. 
