The converse experiment, namely, red (not-fused) females by vermilion fused males also gave, when the wild-type daughters were

back-crossed to vermilion fused males, a linkage value of 27 units. Two 10-day broods were reared from each female. The data given in table 38 show that the percentage of crossing-over does not change as the flies get older. The locus of fused on the basis of all of the data is at 59.5.

Table 37.—P1 vermilion ♀ ♀ × fused ♂ ♂. F1 wild-type ♀ ♀ × F1 vermilion ♂ ♂.

Reference. Females. Non-cross-over ♂ ♂. Cross-over ♂ ♂. Total
♂ ♂.		 Cross-
over
values.
Vermilion. Fused. Vermilion
fused.		 Wild-
type.
79 I 299 93 96 37 36 262 28
80 I 245 93 60 28 27 208 26
81 I 263 101 63 22 40 226 27
Total. 807 287 219 87 103 696 27

Table 38.—P1 wild ♀ ♀ × vermilion fused ♂ ♂. F1 wild-type ♀ × F1 wild-type ♂ ♂.

Reference. Females. Non-cross-over ♂ ♂. Cross-over ♂ ♂. Total
♂ ♂.		 Cross-
over
values.
Vermilion
fused.		 Wild-
type.		 Vermilion. Fused.
52 96 25 30 16 11 82 33
52′ 176 59 64 24 19 166 26
53 60 20 22 9 6 57 26
53′ 76 21 27 11 10 69 31
54 88 35 38 14 16 103 29
54′ 60 22 20 8 9 59 29
57 61 22 20 7 11 60 30
57′ 170 47 54 24 19 144 30
58 128 37 55 14 10 116 21
58′ 144 38 64 16 15 133 23
Firsts 433 139 165 60 54 418 27
Seconds 626 187 229 83 72 571 27
Total 1,059 326 394 143 126 989 27

FORKED.

On November 19, 1912 there appeared in a stock of a double recessive eye-color, vermilion maroon, a few males which showed a novel form of the large bristles (macrochætæ) upon the head and thorax. In this mutation (text-fig. E) the first of several which affect the shape and distribution of the bristles, the macrochætæ, instead of

being long, slender, and tapered (see Plate 1, fig. I), are greatly shortened and crinkled as though scorched. The ends are forked or branched, bent sharply, or merely thickened. The bristles which are most distorted are those upon the scutellum, where they are sometimes curled together into balls.

LINKAGE OF VERMILION AND FORKED.