278 THE AMERICAN NATURALIST [Vol. XL V 



in adult life in many animals, is due to the excess of some 

 hormone in a gamete which thereby becomes male-pro- 

 ducing, in other words, to a dominance of maleness. On 

 the other hand, in the absence of such an excitant, the 

 recessive condition of femaleness would result, with a 

 constant tendency towards quiescence, towards the accu- 

 mulation of reserves of food to nourish the offspring, 

 and the absence in the adult of the brilliant colors, horns 

 and all the well-known and highly specialized secondary 

 sexual characters of the male. 



If it should be proved that maleness is dominant in 

 lepidoptera in which the female is sexually heterozygous, 

 may it not be true, on the other hand, that femaleness is 

 dominant in the forms in which the male is heterozygous 

 for sex, as in Castle's class A? 



I see no inconsistency in these two antithetic categories, 

 but should expect to find in the latter either that the 

 female, and not the male, is the more variable, active and 

 progressive, as in the bee, or that, as in hemiptera, both 

 sexes are in external appearance and in habits much 

 alike. 



In brief, I have tried to point out in this discussion 

 that a different interpretation from that of Castle may be 

 applied to the case of Abraxas, and of Colias also, viz., 

 that these cases, and others that may fall into the same 

 category, differ from those of the well-established class A 

 of Castle in that one is the exact reverse of the other, the 

 female in class A being a homozygous dominant for the 

 sex determiner, whereas in class P> the male is a homo- 

 zygous dominant, and not a homozygous recessive as has 

 hitherto been assumed. The view here set forth not only 

 accounts for the facts of Mendelian inheritance in these 

 two insects equally as well as the other, but has the 

 added advantage of harmonizing with the facts regard- 

 ing the secondary sexual characters in lepidoptera and 

 birds. 7 The high colors and elaborate plumage of the 



tho Biolof/icul 



