THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



the time in which Habrobracon has 'been reared 

 in the laboratory, six mutations in body color 

 have come to light. Three of these mutants, 

 black, honey, and lemon, are fully fertile and 

 can be kept as homozygous stocks with each col- 

 or separate or in any desired combination. The 

 remaining three mutants, cheese, silver, and 

 sooty, have been discarded. Breeding tests have 

 shown that the genes for the first three mutant 

 body colors are linked and are, therefore, on 

 the same chromosome. 



BLACK, bl (body). The recessive mutant black 

 was found among descendants of X-rayed materi- 

 al. Later a recurrence of the same gene ap- 

 peared among the progeny of another X-rayed 

 mated female (A. R. Whiting, 1939b). The fac- 

 tor blackens the animal to an extreme degree, 

 even at higher temperatures. The black pattern 

 is similar to that of wild-type reared at 21- 

 22° C, but yellow areas are considerably light- 

 er, almost cream in fact. The stemmaticum re- 

 mains very black while the praescutum differs^ 

 from that of wild-type at a lower temperature 

 in the shadowy continuation of the median patch 

 to the posterior edge. Dissection shows this 

 pattern to be entirely within the cuticle. 

 Legs are completely black and wings and anten- 

 nae darkened. The whole animal presents a 

 glistening jet-like appearance which becomes 

 even more striking at 19° C. Dissection re- 

 veals in the praescutum a ghost pattern corre- 

 sponding to the light areas of higher tempera- 

 tures, but no trace of the light spots charac- 

 teristic of the mesoscutellum. Mandibular teeth 

 are black. No difficulties are encountered in 



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