THE 



Ohio Journal of Science 



PUBLISHED BY THE 



Ohio Statk University Scientific Society 



Volume XVI M A Y , 1 9 1 6 No. 7 



TABIvE OF CONTENTS 

 Wells — The Comparative Morphology of the Zoocecidia of Celtis occidentalis 249 



CoGAN — Morphological Studies of the Superfamily Jassoidea 299 



Drake— A New Tingid from Tennessee 326 



THE COMPARATIVE MORPHOLOGY OF THE 

 ZOOCECIDIA OF CELTIS OCCIDENTALIS.* 



Bertram W. Wells. 



The purpose of the present paper is three-fold: 



1. To present a survey of the known insect and mite 

 galls of Celtis occidentalis L. 



2. To elucidate the histology of the normal gall bearing 

 parts of the hackberry and that of the galls. 



3. To study comparatively the structures treated, pointing 

 out any significant conclusions and generalizations that may 

 be attained in such a study. 



During the course of personally collecting nearly five hundred 

 types of zoocecidia, the author early discovered that the 

 hackberry and its galls would afford a favorable combination 

 with which to prosecute some anatomical work as outlined 

 above. Four orders of cecidozoons are represented on this 

 species of tree, causing seventeen known kinds of galls, 

 of which sixteen are described in this paper. These orders 

 do not include the hymenoptera whose galls are better known 

 than those of the other orders. The histology of but one of 

 the galls here presented, has been described previously. Since 

 only one species of Celtis occurs in the regions (Ohio and 

 Kansas) from which the material was obtained, no problems 

 of correlation with various host plant species were encountered. 



*Contribution from the Department of Botany, Ohio vState University, No. 95. 

 This paper is the partial fulfillment of the requirements for the degree of master 

 of arts. 



249 



