154 p - w - WHITING. 



the culture vial. If the supply of food is insufficient some of 

 the larvae pupate without spinning cocoons and are shaken into 

 the ether bottle when the first count is made. If returned to 

 the vial they will, in most cases, mature at the expected time. 



The progenies of the heterozygous females above recorded 

 consisted of black males, 104 adults, 5 pupae; orange males, 

 101 adults, 3 pupae; black females, 37 adults, no pupae; orange 

 females, 28 adults, I pupa. The ratio is quite in agreement with 

 expectation and nothing unusual was noticed about the pupae. 

 Some of them would probably have metamorphosed to adults 

 had they been replaced in the culture vial. 



The third heterozygous black sister isolated as a virgin-pro- 

 duced offspring in an unexpected ratio. It was first noticed 

 that the adult progeny were almost all orange and that there 

 was an unusual number of small-sized pupae without cocoons. 

 Examination of the latter, moreover, showed that most of them 

 had black eyes. It was immediately suspected that there was a 

 lethal factor coupled with the normal allelomorph to orange. 

 Consequently all pupae were kept beyond the normal time of 

 eclosion and those that failed to mature were counted as lethal. 

 The black-eyed mother was mated to an orange son in an attempt 

 to get black-eyed daughters carrying the lethal. The total 

 progeny of this lethal-bearing female consisted of black males, 

 4 adults, 28 pupae; orange males, 44 adults, 4 pupae; black 

 females, 2 adults, 3 pupae; orange females, 18 adults, no pupae. 

 Among the females the excess of orange over black adults and 

 the presence of black pupae might seem to indicate partial 

 dominance of the lethal factor. In any case the males show a 

 striking departure from expectation. Black pupae and orange 

 adults w r ould be straights and black adults and orange pupae 

 would be crossovers, except that a few of the pupae might have 

 failed to eclose on account of partial starvation. Among the 

 males of this one fraternity there were 8 crossovers and 72 

 straights or 10 per cent, crossovers. 



The two black-eyed daughters were isolated and later bred to 

 orange sons. One produced black males, 5 adults, 17 pupae; 

 orange males, 23 adults, 6 pupae; black females, 2 adults, 2 pupae; 

 orange females, 2 adults, no pupae. 



