Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLIII. No. 3. — June, 1907. 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE, 

 E. L. MARK, DIRECTOR.— No. 190. 



MATURATION STAGES IN THE SPERMATOGENESIS 

 OF VESPA MACULA TA Linn. 



LIBRARY 

 NEW YORK 

 60TAN1CAI 



By E. L. Makk and Manton Copeland. 



