INTRODUCTION, 
This work on the behavior of twenty-three species of 
solitary wasps was all done in the vicinity of St. Louis, 
Mo., between the years 1917 and 1923. 
As in previous studies, all insect material was sub- 
mitted to experts for identification, and their names ap- 
pear in brackets throughout the work. The photographs 
Were made by the author, and the drawings were made by 
Dr. Gustave Dahms of this eity. A debt of gratitude is 
due to my wife for valuable assistance on the manu- 
Script. 
