R. K. Nabours 147 



general outlines of the pattern of texanus can be clearly seen in the 

 heterozygote. I am not able to distinguish with certainty between any 

 of the other pure forms and the hybrids between them and texanus ; 

 that is, as ordinarily considered, texanus is recessive to all the other 

 species. 



An analysis of the Fo results just described, with their close approxi- 

 mations to the expected ratios of alternative inheritance, shows that 

 the Fi leuconotus were heterozygous, having the gametic constitution 

 AB (allowing A and B to represent the gametes of texanus and leuco- 

 notus, respectively). The leucothorax in the same way were also, 

 heterozygous, having the composition AC {C representing leucothorax), 

 and the behaviour of the midtype strikingly points to its heterozygous 

 leuconotus-leucothorax {BV) character. From this behaviour it seems 

 that we may conclude that the parent male from nature was a texanus- 

 leucouotus heterozygote of the gametic constitution AB, and the 

 females (at least one of them) were texanus-leucothorax {AC) hetero- 

 zygotes and that some of the eggs of at least one of these females had 

 been fertilized by a pure punctofemorata (Z)), or heterozygous texanus- 

 punctofemorata {AD) male, and his D gametes meeting her A gametes 

 made the heterozygous texanus-punctofemorata {AD) specimens of the 

 superficial appearance of punctofemorata (Table I, Fi, and diagram 1 F-,). 



F-, results from inbreeding of the F„ forms of this series. The 

 leuconotus-leucothorax {BC) inbred, as a group culture, gave in F^ 

 251 leuconotus : 452 leuconotus-leucothorax (BC) : 222 leucothorax, 

 the expectation being 281-25 : 4625 : 231-25, respectively. The F, 

 generation leuconotus which came from the inbreeding of F^ leuconotus- 

 leucothorax bred true for three generations and then the culture was 

 destroyed. The F., leucothorax which came from the inbreeding of 

 this F-i leuconotus-leucothorax midtype were carried two generations 

 and bred true. The F, forms of the general appearance of leuconotus 

 were inbred in four cages as follows : (a) 1 male x 1 female, (6) 1 

 male x 1 female, (c) 2 males x 2 females, {d) 2 males x 2 females. Pair 

 (a) gave 10 leuconotus : 3 texanus; pair {h) gave 275 all leuconotus; 

 pair (c) gave 194 leuconotus : 47 texanus; and pair {d) gave 498 leuco- 

 notus : 57 texanus. These results are represented graphically in Table I, 

 F^, as a group culture, as unfortunately they essentially were, because 

 the main attention at this time was being given to the behaviour of 

 the leuconotus-leucothorax midtype and its products, leuconotus and 

 leucothorax, and to the finding of the proper food and other living 

 conditions. However, the results are suggestive; for in cage («) 



