Kinsey: Gall Wasp Genus Cynips 35 
The evidence is all in favor of believing that direct mutations 
have occurred as the result of modifications that must ulti- 
mately be explained in terms of the physics and the chemistry 
of genes. 
A more detailed genetic interpretation of our material must 
for the most part be postponed for a later paper ; but we may 
point out that the graded series of individuals, obtained when 
short-winged species hybridize with long-winged stocks as 
with Cynips hifurca and several species in other genera on 
which we shall publish later, indicate that wing characters in 
these insects may be dependent on multiple factors or per- 
haps on more than one group of such factors. It also appears 
possible that other structural peculiarities regularly associated 
with wing reduction may result from the same mutations of 
one or two genes in groups of linked genes responsible for 
wing characters. A single gene mutation in a single genera- 
tion of insects might then give rise to a very distinct cynipid. 
Such radically new species are usually placed in distinct 
genera, and this probably explains why systematists have so 
often failed to believe that mutation accounts for the origin 
of species in nature. When the mutations are slight, they 
pass as products of Darwinian variation. There is, appar- 
ently, need of a revision of taxonomic procedure in the light 
of genetics data. 
In conclusion, attention should be drawn to the interesting 
case of Cynips bifurca, a variable-winged species which we 
have from only two localities, one in southern Mississippi and 
one in southern Georgia. Both of these stations, however, are 
located well within the range of Cynips aneeps (fig. 50). The 
galls of bifurca and aneeps are identical (figs. 294-295). The 
insects have the same hypopygial spine (figs. 389-390), and a 
peculiar tarsal claw (fig. 350) found nowhere else in the 
genus except among a few of the close relatives of aneeps. 
The figures of the wings (figs. 357-360) and of the whole in- 
sects of bifurca (figs. 338-339) will show that there are two 
distinct types of wings involved: one which is uniformly 
reduced, and the other a truncate wing more like the labora- 
tory mutants called “truncate” in Drosophila. The significant 
thing about the bifurca series is the occurrence of inter- 
mediate individuals with wing-body ratios ranging between 
0.27 and 0.54, body lengths varying from 2.2 to 3.3 mm., and 
