Introduction 
The reception accorded The C ynipi d Gall s of the Pacific Slope (1957) has 
suggested the preparation of a similar work for the region east of the 100 th 
meridian - the Mississippi valley, the northeastern, middle and southeastern 
states and the Gulf Coast as far west as middle Texas. It does not include 
Colorado or the galls of the oaks on the desert ranges in New Mexico and Arizona. 
It lists all the 551 species that have been described or recorded from the area 
(285 on oak and 190 of thse are figured) and in addition gives brief descriptions 
of 72 other galls on oak which have never yet been reared. 
8 
When the writer bgfgan to collect and rear cynipid galls about 1905-6 there was 
only one popular aid to their identification - Beutenraueller's The I nsect-gal ls 
of the Vi cinity of New York City (1904), published by the American Museum. With 
this only a few of the galls of the Chicago area could be named. A detachable 
stem gall might be recognized a3 a Disholcaspis but how many species in that genus 
had been described and from what hosts and locality one did not know. So the 
writer had to work up the American literature of the cynipids which was available 
in the Crerar library. Fully one-third of the galls of the Chicago area proved 
to be undescribed so the writer became a systeraatist instead of working on 
biological problems as originally intended. That preliminary work has now been 
done and time and effort saved for the next worker in the group. 
In 1910 Dalla Torre and Kieffer published a monograph on the Cynipidae in Das 
Tierreich, Lief. 24 bringing the world literature up to 1905. They included keys 
to the genera of the gall makers but they had never seen the genotypes of the 
American genera and knew thse genera only from Ashmead's descriptions. Many 
other new genera have since been proposed. So there is elsewhere now no up-to- 
date key to the genera of the gall makers of the region in any popular form. 
Except in a single instance the older authors reared their adults the next 
spring at the latest from galls they collected. They did not know that many 
galls which drop off in the fall lie on the ground over two winters before any 
5 
