THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



Spin cocoons and ranged in length up to 2.3 

 millimeters as compared with 2,9 millimeters 

 for the normal wild-type wasp. A recurrence of 

 this mutation occurred in the summer of 1934 

 (P. W. Whiting, 1935b) in the offspring of a 

 mated wild-type X-rayed female (dosage about 

 4000 R units) . 



LETHAL, L (pupae). A locus of three allelic 

 factors for lethal effects, wild-type, La, and 

 Lb has been determined by Schaeffer (1945). 

 The lethal effect is regarded as complementary 

 and probably lies to the right of stubby. 



In September, 1943, P. W. Whiting (1943a) 

 described a series of multiple alleles which 

 seem to determine sex in Habrobracon. 



SEX GENE OR CHROMOSOME SEGMENT, x (sex). Nine 

 factors are thus far known in the series, and 

 they are designated by the symbols, xa, xb, xc, 

 xd, xe, xf, xg, xh, xi. The tester stocks are 

 designated as xa/xb, xc/xd, xe/xf, xg/xh, and 

 xa/xi. Evidence of allelism of these sex fac- 

 tors is furnished by the fact that they are all 

 closely linked with the gene, fused. The mul- 

 tiple alleles are regarded as differential chro- 

 mosome segments which have been built up in the 

 early evolution of the Hymenoptera. They may 

 each consist of many genes, which determine the 

 numerous sex differences, structural, function- 

 al, and behaviorlstic , which characterize the 

 Hymenoptera. These genes have the effect that 

 all haploids or homozygous diploids are similar 

 and male, and that heterozygous diploids or 

 combinations of any two different alleles re- 

 sult in females. 



68 



