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THE AMERICAN NATURALIST [Vol.XLVI 



All the males from this cross were again similar to anachoreta, 

 and there was apparently a fair number of them raised. All 

 the females belonged to the anachoreta type, but they are said 

 to have been few in number. 



Thus, although the classes are not all filled, because of the 

 small numbers obtained, the results of the back crosses are in 

 agreement with the hypothesis that we have here a case of sex- 

 linkage of the Abraxas type. 



One interesting point is that in the cross of curtula male by 

 anachoreta female, from which "hundreds" of females were 

 raised, there occurred a single female resembling the males. 

 This furnishes another case of partial sex-linkage, in addition 

 to the. one reported by Bateson and Punnett 3 and the others 

 which I have analyzed in another paper. 4 



In practically all of Federley's cases the offspring of back 

 crosses strongly resembled the hybrid parents, but he explains 

 this as probably due largely to the great mortality of the 

 caterpillars. In only a few cases were more than three or four 

 offspring reared from such crosses. In two such back crosses 

 there appeared caterpillars which had entirely new colors, pre- 

 sumably due to recombination, but unfortunately none of these 

 survived until the imaginal stage. 



A. H. Sturtevant 



a Jour. Genet., 1, 293, 1911. 

 'Jour. Exp. Zool, 12, 499, 1912. 



