THE 



Ohio Journal of Science 



PUBLISHED BY THE 



Ohio State University Scientific Society 



Volume XVIII APRIL, 1918 No. 6 



TABLE OF CONTENTS 



Fenton — The Parasites of Leaf-Hoppers — Part 1 177 



Oberholser— The Common Ravens of North America 213 



DeLong — The Occurence of a Probable Gynandromorph in the Homoptera. . 226 



DeLong— A New Species of Cicadellidse from Wisconsin 228 



BuRRiLL AND Smith— A Preliminary List of the Ants of Wisconsin 229 



THE PARASITES OF LEAF-HOPPERS. 



With Special Reference to the Biology of the Anteoninae. 



F. A. Fenton. 



PART I. 



CONTENTS. PAGE 



I . Introduction 177 



II. Historical 179 



III. Systematic Position 181 



IV. Methods 181 



V. Distribution 181 



Host List 182 



VI. Relations with other parasites 191 



VII. Biology and Life History 192 



VIII. Description of Stages 203 



IX. Internal Anatomy of the Larva 211 



INTRODUCTION. 



The study of the parasites of the leaf-hoppers presents an 

 interesting problem, not only from the practical standpoint, but 

 from the biological as well. The economic status of the leaf- 

 hoppers has been well estabhshed, and as a group they are now 

 considered as including some of the more important insect 

 pests. Therefore, their control by parasitism is significant as a 

 natural check, and their parasites must be considered as dis- 



177 



