ANNALS 
The Entomological Society of America 
Volume VII MARCH, 1914 Number |, 
A STUDY OF DRYOPHANTA ERINACEI (MAYR) AND 
ITS GALL.* 
C. J. TRIGGERSON. 

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CONTENTS 

1. Introduction. 
2. The Life-History of Dryophanta erinacei. APR 23 1914 
A. The agamic form. y 
By The sexual form. ‘ Ce: 
tonal Muse” 
3. The Parasitic and Inquiline Life of the Gall. 
A. Breeding Experiments and their Results. 
B. Parasites and their Relation to the Agamic form otf Dryophanta 
erinacei. 
C. Inquilines, their Relation to Dryophanta erinacei, to the Parasites, 
and to each other during Gall Formation. 
4. The Stimulus to Gall Production. 
A. The Relation of the Malpighian Vessels to Gall Formation. 
B. The Relation of the Oenocytes to Gall Formation. 
Conclusion. , 
Bibliography. 
Dor 
INTRODUCTION. 
The Cynipidae constitute, biologically, one of the most 
interesting families of the Hymenoptera. They have long 
attracted attention, not only from the systematic view-point, 
but also from the view-point of their life-history, the variety 
of the galls they produce or inhabit, their biology, and the 
cause of gall formation. The purpose of this paper is to pre- 
sent an intensive study of one gall-maker Dryophanta erinacet 
(Mayr), discussing its life-history, its parasites, its guests, 
and the cause of gall formation. 
The Oak Hedgehog Gall is rounded or oblong, with the 
surface finely netted with fissures, and more or less densely 
covered with spines. It varies in length from 10-15mm., 
and occurs on both sides of the White Oak leaf. The point 
*Contribution from the Entomological Laboratory of Cornell University. 


