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Indiana University Studies 
The close affinities of the Eurasian and Pacific American 
subgenera of Cynips, and the more unique nature of the 
eastern American subgenera suggests that the migration be- 
tween Eurasia and North America was by way of the 
Alaskan-Siberian land bridge, rather than by way of former 
land connections between Labrador, Greenland, Iceland, and 
northern Europe . 1 The migration of the first group of Cynips 
FIG. 8. PHYLOGENETIC ORIGINS, SUBGENUS CYNIPS 
from its center of origin in the Southwest, to our Pacific 
Coast, and finally across Alaska into Siberia, must have 
occurred before the Great Basin became arid, and while the 
Alaskan-Siberian land connections were still enjoying a 
climate mild enough to have supported an oak forest. From 
the preceding table it will be seen that fossil oaks are known 
to have occurred in both Siberia and Alaska as late as the 
Eocene, and the land connections between the two continents 
were continuous thru the late Miocene and intermittently 
existent at later periods. Berry, however, expresses it as his 
1 Thruout this part of this study I have had the criticism of Dr. C. 
A. Malott and Dr. J. W. Beede of the Geology Department of Indiana 
University. Geologic data pertaining to this section are summarized in 
such texts as Miller’s Introduction to Historical Geology (1916) and 
Schuchert’s Historical Geology (1924). Berry (1923) and Trelease 
(1924) summarize the paleontological record of Quercus. 
