34 
Indiana University Studies 
gemmula 
. . . 0.27 
advena 
. . .0.17-0.23 
bisex. form . . . . 
... 1.30 
echinoides . . . 
0.19 
pezomachoides 
hirta 
cincturata 
. . . 0.16 
undulata .... 
0.23 
ozark 
... 0.14 
packorum . . . 
0.28 
wheeleri 
... 0.15 
obtrectans ... 
0.35 
pezomachoides . . . 
. . . 0.23 
opima 
0.26 
derivatus 
... 0.18 
scelesta 
0.21 
erinacei 
. . . 0.22 
macrescens . . 
0.21 
bisex. form . . . . 
... 1.30 
hirta 
0.23 
It seems warranted to conclude that insects differing as 
thoroly as these long-winged and short-winged Cynips may be 
among the most closely related species in existence. Or, in- 
terpreting this statement, we may believe that diverse species 
may originate directly — that is, by direct mutation — from 
each other. It should be apparent to anyone familiar with 
the laboratory Drosophila melanog aster that these subapterous 
Cynipidae are quite comparable to the subapterous mutants 
which geneticists have shown to have arisen by direct muta- 
tion in the laboratory from long-winged Drosophila stock 
(e.g., see the summary publications of Morgan, Bridges, and 
Sturtevant cited in our bibliography) . The explanation that 
will suffice for Drosophila will probably need no essential 
modification for the gall wasps, but the Cynipidae may estab- 
lish the importance of the laboratory mutations as materials 
from which species populations actually arise. 
Among none of the Cynipidae is there evidence that the 
modified wings have developed by the sort of fluctuating 
variation and the essentially orthogenetic selection conceived 
by the Neo-Darwinians. Altho there are many short-winged 
species which occur directly beside their long-winged relatives, 
there are no intermediate forms as we might expect from 
fluctuating variation, with the possible exception of Cynips 
hi f urea which appears to be hybridizing today with the long- 
winged, parental stock. 
There seems no basis for believing the shortened wings or 
any of the concomitant variations of any adaptive value to 
any of these insects. The short wings are not confined to 
warmer or colder climates, and long- and short-winged forms 
of various species are active at the same season in the same 
localities. The field data suggest nothing as to the survival 
value of these outstandingly basic modifications of structure. 
