In the repetition of a cross between a white miniature male and a vermilion pink male (December 1913), the F_2 ratios among the males were seen to be very much distorted because of the partial absence of certain classes (Morgan 1914_c_). While it was suspected that the disturbance was due to a lethal, the data were useless for determining the position of such a lethal, from the fact that more than one mother had been used in each culture. From an F_2 culture that gave practically a 2:1 sex-ratio, vermilion females were bred to club males. Several such females gave sex-ratios. Their daughters were again mated to vermilion males. Half of these daughters gave high female sex-ratios and showed the linkage relations given in table 55. TABLE 55.--_Linkage data on club, lethal 3, and vermilion, from Morgan, 1914c_. +----------+-----------------------------------------------------------+ | | Males. | | +-----------+--------------+------------------+-------------+ | | c_1 | c_1 l_3 v | c_1 v | c_1 l_3 | | Females. | ------- | --+------ | ----+- | --+--+-- | | | l_3 v | | l_3 | v | | +-----------+--------------+------------------+-------------+ | | Club. | Wild-type. | Club vermilion. | Vermilion. | +----------+-----------+--------------+------------------+-------------+ | 588 | 182 | 28 | 11 | 1 | +----------+-----------+--------------+------------------+-------------+ {74} Lethal 3 proved to lie between club and vermilion, 13 units from club and 5 from vermilion. The same locus was indicated by the data from the cross of vermilion lethal-bearing females by eosin miniature males. The complete data bearing on the position of lethal 3 is summarized in table 56. On the basis of this data lethal 3 is located at 26.5. TABLE 56.--_Summary of linkage data on lethal 3, from Morgan, 1914c_. +---------------------+--------+--------+------------+ | Gens. | Total. | Cross- | Cross-over | | | | overs. | values. | +---------------------+--------+--------+------------+ | Eosin lethal 3 | 1,327 | 268 | 20.2 | | Eosin vermilion | 1,327 | 357 | 27.0 | | Eosin miniature | 3,374 | 967 | 29.0 | | Club lethal 3 | 222 | 29 | 13.0 | | Club vermilion | 877 | 161 | 18.4 | | Lethal 3 vermilion | 1,549 | 105 | 6.8 | | Lethal 3 miniature | 1,481 | 138 | 9.3 | | Vermilion miniature | 1,327 | 31 | 2.3 | +---------------------+--------+--------+------------+ LETHAL 3a.