82 
Indiana University Studies 
It will be very interesting to discover whether there are any 
differences in the biology of ohtusilohx from Texas. 
The great similarity of the alternate generations in this 
species first suggested to me that the heterogeny of some 
Cynipidse is a development of seasonal dimorphism. The 
differences in these insects are wholly those of size and shape 
of the abdomen, which are readily correlated with the differ- 
ences in modes of reproduction. No one would differentiate 
the two insects but that one generation is agamic and the 
other bisexual, and the galls are rather different. The differ- 
ences in the galls are clearly results of the states of the plant 
at the two seasons when the eggs are laid. 
Each of the four varieties is confined to a single species 
of oak, and the several records of more than a single host 
are probably incorrect, being based on galls only. Each of 
the several faunal areas 'of the eastern half of the United 
States may have distinct varieties for each host, so about 
sixty varieties may be discovered. In addition to the material 
described here I have galls but no insects from Quercus Prinus 
from Mitchell, Indiana. The following references are to this 
species, but I cannot now assign them to particular varieties ; 
they belong to faunal areas not covered by the described 
varieties. 
Cyni'ps quercus batatus Thomess, 1879, Trans. 111. Hort. Soc. for 1878, 
p. 198. 
Neuroterus noxiosus Gillette, 1888, 27th Rpt. Agric. Mich., p. 471; 1889, 
Psyche, V, p. 187. Nason, 1906, Ent. News, XVII, p. 8. Cook, 
1910, Mich. Geol. and Biol. Surv. Publ., I, p. 30. Beutenmuller, 
1910 (Iowa record), Bull. Amer. Mus. Nat. Hist., XXVIII, p. 118. 
Cynips quercus-bcitatus Packard, 1890, 5th Rpt. U.S. Ent. Comm., p. 
Ill (Canada). 
Neuroterus batatus Beutenmuller, 1910 (Ohio, Illinois, and Colorado 
records). Bull. Amer. Mus. Nat. Hist., XXVIII, p. 117. Brodie, 
1896, Ann. Rpt. Forest Ont., p. 117, fig. 3. Cook, 1910, Mich, Geol. 
and Biol. Surv. Publ., 1, p. 30. Washburn, 1918, 17th Rept. State 
Ent. Minn., p. 180. 
The following references do not apply to this species: 
Neuroterus batatus Ashmead, 1890, Colo. Biol. Assoc. Bull., I, p. 38 
(is probably an underscribed species if it belongs to this genus). 
Neuroterus quercus-batatus Fullaway, 1911, Ann. Ent. Soc. Amer., IV, 
p. 334 (is Neuroterus quercicola pacificus Beutenmuller). 
Neuroterus noxiosus Thompson, 1915, Amer. Ins. Galls, pi. 1, fig. 16 
(is- a variety of Plagiotrichus petiolicola (Bassett).) 
