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Show 126 MR. L. DONCASTER AND REV. G. II. RAYNOR ON [Feb. 20, insects used. Only three of these original pairings gave larvae which reached maturity. Their results are given in Table I. TABLE I. No. of Exp. $ PARENT. rf PARENT. OFFSPRING. 03.3... ^ sordiata X £ sordiata gave 22 sordiata £, 25 sordiata $ . 03.6... $ prunaria X <? sordiata „ 27 sordiata $, 7 sordiata <j?, 1 prunaria 9 . 03.4... ^ prunaria X $ prunaria „ 27prunaria $, 1 sordiata £, 40 prunaria ^ . These figures immediately suggested that the banded var. sordiata was a simple Mendelian dominant over the unhanded prunaria type. The next year's work confirmed this conclusion ; and it must be supposed that the single prunaria among the offspring of 03.6 and the single sordiata in 03.4 were due to accident. The larvae, when they first hatch, are exceedingly minute, and when the food is changed it is difficult to be certain that no larva clings to the hands and gets transferred to the wrong box. A n inspection of the moths from 03.3 showed that about half of them have the brown bands on the wings, with plain orange or yellow centres, but that the other half, in addition to the banding, have the orange centres speckled as in the typical prunaria. Sometimes the speckling is very faint, so that it is hard to give exact numbers of each type, but approximately among the offspring of 03.3 the numbers are 24 speckled and 23 plain. In 03.6 all were speckled. This suggests that the speckled character of prunaria is dominant over the plain of sordiata at the same time that the banding of the latter dominates over its absence in the former; in this way a heterozygote can be distinguished from a pure sordiata. In 1904, 36 pairings were made, of which 24 yielded imagos in 1905. Their results are given in Tables II.-VII. T A B L E II.-Prunaria 2 X prunaria <S . No. of. Exp. 04. 1 2 3 4 10 12 13 Total prun. (J. 8 15 1 11 7 3 45 1 prun. $. 2 8 5 6 1 4 26 sord. (J. 1 1 sord. $. |