THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



the region was compared with a region of simi- 

 lar length (22,3) to the right of lemon, namely, 

 cantaloup to honey. Coincidence for black- 

 lemon, and lemon-cantaloup, was ' found to be 

 1.07, while the lemon-cantaloup, and cantaloup- 

 honey, was 0.28. Clark suggests that the reason 

 for the lack of interference between the black- 

 lemon, and the lemon-cantaloup, regions is' that 

 the spindle fiber attachment center is located 

 near lemon. If such is the case, then the re- 

 gion of the sex gene is about 150 units away 

 from the spindle fiber attachment region. 



A third group of genes designated as the 

 "red" group (Anderson and P. W. Whiting, 1939) 

 consists of five loci with a map distance of 74 

 units. This group forms the right end of the 

 sex chromosome. Twelve other genes are also 

 located on this first chromosome. For their 

 position and crossover value see Fig. 17 or 

 Table II. 



A second chromosome, or linkage group two 

 (II) of three loci, 35 units in length, has been 

 identified (P. W. Whiting and Benkert, 1934). 

 This linkage group consists of three mutants, 

 kidney, orange, and miniature. A three point 

 experiment planned to determine the relative 

 positions of kidney, orange, and miniature , gave 

 7.5 per cent crossing over between orange and 

 miniature, and 27,5 per cent crossing over be- 

 tween miniature and kidney, with 2.8 per cent 

 double crossing over. From these data it may 

 be concluded only that miniature lies about 

 one-fourth the distance from orange to kidney 

 (Fig. 17). 



The third chromosome, or linkage group three 

 (III), of four loci is approximately 44 units 



108 



