NEW DATA. 



REDUPLICATED LEGS. 



31 



In November 191 2 Miss Mildred Hoge found that a certain stock 

 was giving some males whose legs were reduplicated, either completely 

 or only with respect to the terminal segments (described and figured, 

 Hoge, 1915). Subsequent work by Miss Hoge showed that the con- 

 dition was due to a sex-linked gen, but that at room temperature not 

 all the flies that were genetically redupHcated showed reduplication. 

 However, if the flies were raised through the pupa stage in the ice-box 

 at a temperature of about 10° to 12° a majority of the flies which were 

 expected to show reduplication did so. The most extremely redupli- 

 cated individual showed parts of 14 legs. 



In studying the cross-over values of reduplicated, only those flies 

 that have abnormal legs are to be used in calculation, as in the case 

 of abnormal abdomen where the phenotypically normal individuals 

 are partly genetically abnormal. Table 4 gives a summary of the 

 data secured by Miss Hoge. 



Table 4. — Summary of linkage data upon reduplicated legs, from Hoge, igiS- 



The most accurate data, those upon the value for reduplicated and 

 vermilion, give for reduplicated a distance of 1.7 from vermilion, either 

 to the right or to the left. The distance from white is 29, which would 

 place the locus for reduplication to the left of vermilion, which is at 33. 

 The data for bar give a distance of 21, but since bar is itself 24 units 

 from vermilion, this distance of 21 would seem to place the locus to 

 the right of vermilion. The evidence is slightly in favor of this position 

 to the right of vermilion at 34.7, where reduplicated may be located 

 provisionally. In any case the locus is so near to that of vermilion 

 that final decision must come from data involving double crossing-over, 

 i, e., from a three-locus experiment. 



LETHAL I. 



In February 191 2 Miss E. Rawls found that certain females from a 

 wild stock were giving only about half as many sons as daughters. 

 Tests continuing through five generations showed that the sons that 

 appeared were entirely normal, but that half of the daughters gave 

 again 2 : i sex-ratios, while the other half gave normal i : i sex-ratios. 



