Kinsey: Gall Wasp Genus Cynips 
67 
Atrusca , and Acraspis, could have spread to the north in the 
Rocky Mountain area, to the south in Mexico, and to the east 
toward the Atlantic Coast. On the other hand, if the genus 
were assumed to have arisen in Europe or Asia, it is difficult 
to understand why the Eurasian affinities should have been 
maintained onto the Pacific Coast of North America, and a 
primary subdivision of the genus not effected until the group 
reached the Southern Rockies. However, we are completely 
ignorant of the present-day occurrence of the genus in most 
of Asia (on pp. 447 to 453 we show that the species reported 
from Japan do not belong to the genus), and further dis- 
coveries may throw light on Asiatic beginnings of the group ; 
but from the available data we would presume the south- 
western American origin for the genus and its initial differ- 
entiation in that area. 
That the point of origin was not north of central Arizona 
or New Mexico is indicated by the occurrence of numerous 
short-winged species both north and east of the region, while 
not a single short-winged species of the group is to be found 
in the southern halves of those states. We have already 
shown that the short-winged species represent more special- 
ized developments of the long-winged stocks. One short- 
winged and one long-winged species of Cynips is known from 
central Mexico, but our knowledge of the gall makers of that 
country is still insufficient to make it certain that our genus 
did not originate somewhere in northern Mexico. 
It is interesting to find that Trelease (1924:34), consider- 
ing the origin of the American oaks, states that “their 
primary center of distribution appears to have been what is 
now Arizona.” Trelease’s conclusion is based in part upon 
the opinion that the widely distributed Cretaceous oaks have 
left no descendants in present-day groups, and that the 
existent white oaks of Europe and Asia, and both the white 
and black oaks of America have developed from the type 
represented by the European, Tertiary Quercus Palaeo-Ilex. 
This type is presumed to have reached America at some time 
previous to the Cenozoic. Berry’s criticism (1923:139) of 
this conclusion seems to be based upon a mis-interpretation 
of Trelease’s involved presentation of the argument, but the 
matter needs more data than seem to have been derived from 
the Cretaceous fossils that are often dubiously referred to 
Quercus . 
