THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



Lemon thus shows a striking contrast to honey, 

 and is partially dominant to wild-type. Pale 

 basal segments and characteristic lemon prae- 

 scutal pattern are dominant whereas general body 

 color of the heterozygote resembles wild-type. 

 There are present on the praescutum two dis- 

 tinct anterior bands sharply divided by a light 

 line, and below these, irregular spots, often 

 asymmetrical. Study of the cuticle of the lemon 

 thorax by means of sections and removal from 

 tissue underneath shows that the black pattern 

 is in the cuticle itself. The spotted effect 

 results from internal structures showing through 

 the transparent portions which correspond to 

 the yellow regions in the wild-type and other 

 mutant forms. The two praescutal bands, char- 

 acteristic of lemon, outline more accurately 

 the muscle masses beneath than does the solid 

 patch of non-lemon forms, for dissection re- 

 veals a definite longitudinal division in the 

 muscle masses of this region in all color types. 

 This dividing line in the praescutal pattern is 

 mentioned by Schlottke (1926) as appearing in 

 some wild-type individuals at high temperature, 

 and it sometimes shows in honey as a darker 

 line in the center of the median praescutal 

 patch. In lemon, however, it is consistently 

 present and more extreme. Lower temperatures* 

 change the black pigment of the lemon mutant 

 less strikingly than that of wild^type or black. 

 The black areas never become as intense or 

 widespread, but in spite of this there is a 

 striking lightening of yellow. The females of 

 this mutant are fully fertile, and the males 

 are of normal viability (A. R. Whiting, 1939b). 



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