Kinsey: The Genus Neuroterus 
13 
have been discussed in an earlier paper of mine (1920, Bull. 
Amer. Mus. Nat. Hist., XLII, pp. 357-402). Still others are 
based on more recent data which will have to be explained 
in a special paper if the present treatment of Neuroterus 
does not furnish sufficient evidence. There are other sources 
of phylogenetic data which are not available in this genus. 
From the above methods of reasoning, Neuroterus appears 
to be, on a whole, a very primitive genus, having the closest 
relatives in such groups as Comysodryoxenus, Bassettia, and 
Plagiotrichus. But in many respects, Neuroterus shows a 
very separate evolution from any other Cynipidse, some 
am.ount of specialization being indicated by the extreme re- 
duction of the thoracic sculpturing, the reduction of size, the 
restriction to white oaks, and the occurrence of heterogeny 
(with complete agamy in some species?). 
Neuroterus must be rated as quite but not entirely primi- 
tive, having had both a forward and a degenerative evolution. 
It belongs to the more primitive of the oak-inhabiting Cyn- 
ipidse, and in consequence furnishes much information on 
the phylogeny of characters of higher gall wasps, but it is 
not entirely representative of the ancestral type of these 
Cynipini. The genus is on a whole a compact unit, the species 
in some regards being remarkably uniform, but in some other 
regards having had sufficient evolution to afford much inter- 
esting material for study. In this respect, Neuroterus is not 
as compact a group as Disholcaspis, Amphibolips, or Heter- 
oecus, but there has been less evolution in this genus than in 
Diplolepis. 
The detailed study of the phylogeny of each of the species 
of Neuroterus is made in the following pages in connection 
with the taxonomic descriptions, and the whole is summarized 
in figure 1 at the end of the paper; and the utilization of this 
information in a scheme of classification has been treated in 
the preceding paragraphs. 
HOST RELATIONS 
The genus Neuroterus is strictly confined to white oaks 
(Lepidobalanus) , and this is the most interesting aspect of 
its host relations. That this genus does not occur, as do the 
most primitive Cynipidse, on a variety of herbaceous plants, 
and that there is a restriction to a single subgenus of the 
