Page:The Gall Wasp Genus Cynips.pdf/19



We should have had thousands of specimens of every one of these insects. Failing that, our conclusions on certain matters have been based to a large degree upon the more available species, and the intensive study of those species has offered interpretations of our smaller bodies of data which would not otherwise have been possible.

To obtain data on geographic distribution and the relation of geographic isolation to the origin of species, I have attempted to secure representative series of each Cynips from as many and as widely distributed localities as possible. It was in the fall of 1917 that I made my first collections of the genus, and in the twelve years that have intervened I have travelled over thirty-two thousand miles in the pursuance of the distributional data originating from my own collections. In 1919 and 1920 I went as a Sheldon Travelling Fellow of Harvard University to the South and to the Far West. For a number of years I have been relieved from part of my teaching to pursue research under a grant of the Waterman Institute of Indiana University, and in this connection I have engaged in extensive field work thruout the northern Middle West and in the southeastern quarter of the United States. In the course of these contacts with gall wasps in the field, as well as thru the longer hours spent over the microscope, I have gradually developed my present concept of species.

My own cross-country field work has been supplemented with collections made thru every season and in some cases for several years by collectors working in their native areas. Over a hundred such collectors have contributed data, sending material from localities in nearly every one of the United States