6 
Indiana University Studies 
In this study two terms, types and species, are used with 
their generic meanings, and not in the restricted senses usu- 
ally employed in entomology. The term type is applied to 
both holotypes and paratypes and any other special sort of 
types, and I have used the more special terms wherever nec- 
essary. And a species is one or more varieties, and it is 
not the first variety described (the ‘Typicah' variety) as one 
might infer from the usual treatment of varieties. The de- 
scriptions and remarks under the specific titles should apply 
fully to all varieties of the species, and the typical variety 
should be treated just as specially as any other. 
The perpetuation of an original quercus as part of a 
trivial name is not satisfactorily dealt with by the Inter- 
national Code of Nomenclature. Until the matter is finally 
treated by the Commission, I am completely eliminating 
quercus or q., hyphenated or not, from specific names. This 
introduces no new element in the problems, inasmuch as the 
majority of American students have long followed this prac- 
tice. 
The holotypes of all but two of the new varieties are 
deposited with The American Museum of Natural History, 
and paratypes are distributed in many of the other museums, 
and in many cases will be available as loans or exchanges 
from my own collection. 
CLASSIFICATION 
A good classification must be based on all the available 
data. It is relatively easy to make a classification on the 
basis of characters of any one sort, but unfortunately it is 
more difficult to co-ordinate several sorts; and yet no classi- 
fication is an adequate picture of conditions as they exist 
in nature if we refuse to consider any sort of expression of 
those conditions. For this reason in the present treatment 
of Neuroterus there is an attempt to recognize insect mor- 
phologies, gall characters (as an expression of insect physi- 
ology), the degree of differences between sexes, host and 
geographic distributions, life histories, and any other data 
available. 
A classification of any number of items in biology should 
provide the most convenient system of cataloging compatible 
with the expression of our fullest knowledge of evolutionary 
