Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLI. No. 33. — May, 1906. 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE. 

 E. L. MARK, DIRECTOR. — No. 177. 



THE EFFECTS OF INBREEDING, CROSS-BREEDING, 



AND SELECTION UPON THE FERTILITY AND 



VARIABILITY OF DROSOPHILA. 



By W. E. Castle, F. W. Carpenter, A. H. Clark, S. O. Mast, 

 and W. M. Barrows. 



