ISO E. W. SEYSTER. 



directly proportional to the increase in the area of the eye, and 

 facet-size is therefore a constant within these limits. 



5. Light, and amount of food, as they occur in these experi- 

 ments are not important factors in the determination of facet 

 number. 



6. Temperature is effective only during the larval period. 



ACKNOWLEDGMENT. 



This work was done under the direction of Dr. Charles Zeleny 

 and I wish to express my thanks to him for his inteVes in the 

 problem and for his many suggestions while it was in progress. 



