Shifted appeared (January 1913) in a stock culture of vermilion dot. The chief characteristic of this mutant is that the third longitudinal vein (see text-fig. F) does not reach the margin as it does in the normal fly. The vein is displaced toward the fourth throughout its length, and only very rarely does it extend far enough to join the marginal vein. The cross-vein between the third and the fourth veins is often absent because of the shifting. The flies themselves are smaller than normal. The wings are held out from the body at a wide angle. The two posterior bristles of the scutellum are much reduced in size and stick straight up--a useful landmark by which just-hatched shifted flies may be recognized, even though the wings are not expanded. LINKAGE OF SHIFTED AND VERMILION. Since shifted arose in vermilion, the double recessive shifted vermilion was available for the following linkage experiment: shifted vermilion males by wild females gave wild-type males and females which inbred gave the data shown in table 46. [Illustration: FIG. F.--Shifted venation. The third longitudinal vein is shifted toward the fourth and fails to reach the margin. Cross-vein between third and fourth longitudinal veins is lacking.] Disregarding the eye-color, the following is a summary of the preceding results: wild-type [female], 1,001; wild-type [male], 437; shifted [male], 328. The result shows that shifted is a sex-linked recessive. The data of table 46 show that the locus of shifted lies about 15 units on one side or the other of vermilion, which from the calculated position of vermilion at 33 would give a position for shifted at either 18 or 48 from yellow. TABLE 46.--_P_1 shifted vermilion [male] [male] x wild [female] [female]. F_1 wild-type [female] x F_1 wild-type [male] [male]._ Key to columns: A: Wild-type [female] [female]. B: Non-cross-over [male] [male], Shifted. C: Non-cross-over [male] [male], Wild-type. D: Cross-over [male] [male], Shifted. E: Cross-over [male] [male], Wild-type. F: Total [male] [male]. G: Cross-over values. +--------------+---------+------+------+-------+-------+-------+------+ | Reference. | A | B | C | D | E | F | G | +--------------+---------+------+------+-------+-------+-------+------+ | 13 | 345 | 79 | 115 | 8 | 25 | 227 | 15 | | 29 | 68 | 20 | 32 | 3 | 4 | 59 | 12 | | 30 | 191 | 37 | 54 | 5 | 13 | 109 | 17 | | 31 | 151 | 41 | 65 | 17 | 13 | 136 | 22 | | 33 | 133 | 49 | 40 | 4 | 6 | 99 | 10 | | 34 | 113 | 56 | 59 | 9 | 11 | 135 | 15 | +--------------+---------+------+------+-------+-------+-------+------+ | Total. | 1,001 | 282 | 365 | 46 | 72 | 765 | 15 | +--------------+---------+------+------+-------+-------+-------+------+ {63}