Proceedings of the American Academy of Arts and Sciences. 

 Vol. XXXIII. No. 21. —June, 1898. 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE, 

 E. L. MARK, DIRECTOR, No. XCIL 



A CONTRIBUTION TO THE STUDY OF INDIVIDUAL 

 VARIATION IN THE WINGS OF LEPIDOPTERA. 



By William L. W. Field. 



