168 Inheritrnice and Evolution in Orthoj>fera J 



tlie phenomenon appear to be due to an inherited seasonal rhythm ; tor 

 the fourth generation progeny, coming from the short winged genera- 

 tion III, which had grown from July to February, the time required 

 for two generations of their brother and sister generation II and III 

 progeny, behaved exactly as the progeny F^ of the long winged and 

 short winged which had come from the fourth generation of the same 

 line. 



(3) Equivalence in the hybrids. From the examination of the 

 pigmental compositions of the colour patterns of the pronota so far 

 as it has progressed, the conclusion seems to be justified that the 

 peculiar pigmental elements of each of the patterns of the pronota of 

 the parents are present in the pattern of the pronotum of their hybrid 

 in about, if not in exactly, equal proportions. With this knowledge in 

 mind it does not appear that the terms dominant and recessive are 

 applicable at all to these grouse locusts ; they appear to be, in respect 

 to their representation in the composition of their hybrids, perfectly 

 equivalent, or, to use Davenport's term, equipotent (2). If only the 

 superficial appearances be taken into consideration, Bateson's terras of 

 cpistatic, for the colour most apparent, and hypostatic, for the colour 

 less apparent, may be employed in some instances (1). 



The fact that the heterozygote pattern in the end result is so 

 equivalently made up of the respective patterns of the parent species 

 seems to warrant the suggestion that the somatic part of the hybrid 

 zygote (fertilized hybrid ovum) in its somatogenesis may be in some 

 way alternative, giving the character of the one, and then the character 

 of the other, parent to the resulting soma of the hybrid ; just as the 

 gametal part of this same liybrid zygote in its gametogenesis is usually 

 most certainly alternative, giving a gamete for the one, and then a 

 gamete for the other parent. 



(4) The " Genotype Conception." These forms approximately, if 

 not completely, fulfil the requirements of the description of biotypes 

 by Johannsen. The evidence points to the fact that in none of the 

 inheritance behaviour observed is there any transmission of the qualities 

 of the parent to the offspi-ing(5). (There have been five exceptions 

 noted.) The regular 1:2:1 ratio result of the inbreeding of hybrids, 

 the 1 : 1 ratio I'esult of the crossing of hybrids with their parent types, 

 and the 1:1:1:1 I'atio result of the interbreeding of hybrids indicate 

 that the qualities of the parents, as well as the qualities of the progeny, 

 are determined by the nature of the germinal material, and that the 



