STUDIES ON THE PARASITIC WASP, HADROBRACON 

 BREVICORNIS (WESMAEL). 



i. GENETICS OF AN ORANGE-EYED MUTATION AND THE PRO- 

 DUCTION OF MOSAIC MALES FROM FERTILIZED EGGS. 



p. w. WHITING, 



ST. STEPHEN'S COLLEGE, ANNANDALE-ON-HUDSON, N. Y. 



INTRODUCTION. 



In a previous paper (1918) I gave a brief account of the general 

 biological relationships and the method of sex-determination in 

 the parasitic wasp, Hadrobracon brevicornis (Wesmael). The 

 experiments there reported were begun in the fall of 1916 and 

 continued through the winter. Difficulties in rearing the host 

 caterpillars in sufficient quantity induced me to abandon the 

 work on the wasp and to concentrate on the host, the Mediter- 

 ranean flour-moth, which was also being investigated genetically. 

 When these technical difficulties were overcome, the work with 

 Hadrobracon was renewed and has been continued since June, 

 1919. During the summer of 1919, the wasps were bred at the 

 Marine Biological Laboratory, Woods Hole, Massachusetts; 

 during the winter of 1919-20, at Franklin and Marshall College, 

 Lancaster, Pennsylvania; and during the summer of 1920 at the 

 Carnegie Station for Experimental Research, Cold Spring Harbor, 

 Long Island. The work is being continued at St. Stephen's 

 College, Annandale-on-Hudson, New York. 



My grateful acknowledgments are due for the hospitality of 

 the Woods Hole Laboratory and of the Carnegie Station at 

 Cold Spring Harbor. I am also indebted for financial aid to the 

 Carnegie Institution of Washington and to the American Associa- 

 tion for the Advancement of Science from which I have received 

 two grants for research. Mrs. Whiting has given me valuable 

 assistance in the course of the work. 



A type of reproduction in which virgin females produce only 



males while mated females may produce either males or females 



42 



