CROWDING AND SEX DETERMINATION 



301 



experiments in which he fed a known number of M. suhnigrescens 

 eggs to the common New England grasshopper, Melanus femur- 

 rubrum. 



In four cases of relatively heavy infestation a total of 100 eggs 

 were fed, from which 86 parasites were reared, all of which were 



TABLE XXXIV 



Showing the Results of Feeding Grasshoppers with 



Known Numbers of Mermithidae Eggs upon the 



Sex of the Developed Nematodes 



(Data from Christie) 



Number of Eggs Fed 



SO- 



Females 



* Camnula pellucida used as host insect. 



males. In the relatively light infestations, 102 eggs were fed, usual- 

 ly 5 to each grasshopper; of these, 73 parasites were reared, of 

 which 6, or 8 per cent, were males. 



Caullery and Comas (1928), stimulated by the early reports of 

 the work just reviewed, examined the distribution of sexes in the 

 nematode worm, Paramermis contorta, which is a parasite upon a 



