12 
Indiana University Studies 
The third antennal segment is most primitive when most 
nearly the size of the fourth. 
The third antennal segment of the male is most primitive 
when least curved. 
A considerable reduction in size indicates specialization. 
Both an entirely smooth thorax and one very much sculp- 
tured indicates specialization. 
Considerable enlargement of the eye, as often in the male, 
indicates specialization. 
The toothed tarsal claw indicates specialization, but is 
by no means an invariable consequence of specialization. 
The closer the similarity of the female and male, the more 
primitive the species. 
Polythalamous galls are more primitive than monothala- 
mous galls (except anther galls) , 
The smaller the amount of hypertrophy the more primitive 
the gall (with exceptions) . 
Inseparable galls are more primitive than separable galls 
(except anther galls). 
Regular form and special structures (unless an increased 
pubescence, not long wool) indicate specialization. 
Similarity of very simple galls is no indication of relation- 
ships but rather an expression of similar primitiveness. 
The more limited the number of different plant tissues 
ever affected, the more specialized the species. 
The greater the number of species or (more particularly) 
the number of groups of oaks serving as hosts, the more 
primitive the insect. 
The greater the number of faunal areas (not the square 
miles) in its range, the more primitive the insect. 
The more nearly equal the numbers of the sexes in a 
bisexual generation, the more primitive the species. 
Two bisexual generations alternating in a year are more 
primitive than bisexual and agamic in alternation, and two 
agamic generations in a year are more specialized. 
The more dissimilar the galls of alternate generations 
(making allowances for differences in plant tissues attacked, 
direct seasonal effects such as rate of growth, etc.), the more 
specialized the species. 
Some of these conclusions are generally accepted in ento- 
mology, Some of those which apply particularly to Cynipidse 
