EGG PARASITES OF THE GIPSY MOTH. 183 



In order that some idea may be had of the conditions which actually 

 prevail in the open in Japan, results of the dissection of 43 eggs 

 from Japanese importations are given below. Many other eggs were 

 dissected, in some of which the tale was too complicated to be un- 

 raveled, and it is, of course, necessary to leave out of consideration 

 here the results of those dissections which were made before the 

 significance of that which was found was fully recognized. 



In the f ormulaB which follow the symbols are to be read as follows : 



X = Parasitized by; + =Superparasitized by. 



Thus the conditions represented in the figure to which attention 

 has already been drawn would be expressed: 



Porthetria dispar X Anastatus X Schedius. 



+ Schedius. 

 + Schedius. 



The host relations revealed by dissections of eggs from which Pachy- 

 neuron emerged are similarly indicated as follows : 



Dispar X Schedius X Pachyneuron (20 times). 

 Dispar X Schedius X Pachyneuron. 



+ Pachyneuron (1 time). 

 Dispar X Schedius. 



+ Schedius X Pachyneuron (3 times). 

 Dispar X Schedius. 



+ Schedius. 



+ Schedius. 



+ Schedius. 



+ Schedius X Pachyneuron (1 time). 

 Dispar X Anastatus X Pachyneuron (1 time). 

 Dispar X Anastatus. 



+ Schedius X Pachyneuron 1 time). 



Dissections of eggs from which Tyndarichus emerged resulted as 

 follows : 



Dispar X Schedius X Tyndarichus (11 times). 

 Dispar X Schedius. 



+ Schedius X Tyndarichus (2 times). 

 Dispar X Schedius. 



+ Schedius X Tyndarichus. 



+ Tyndarichus (1 time). 

 Dispar X Schedius X Pachyneuron. 



+ Tyndarichus (1 time). 

 Dispar X Anastatus X Tyndarichus (1 time). 



Mention has already been made of the parthenogenesis of Schedius, 

 and the fact that only males were produced in the first attempt of 

 successful reproduction experiments in which only a single female 

 was available. Numerous subsequent experiments have demon- 

 strated beyond question that arrhenotoky is the rule and that excep- 

 tions are rare if they ever occur. 



