INTRODUCTORY. 



21 



The sex-linked factors of Drosophila. 



Gen. 



White. 



Rudimentary 

 Miniature. . . 

 Vermilion . . . 



Yellow 



Abnormal . . . 



Eosin 



Bifid 



Reduplicated 



Lethal 1 



Lethal la*. . . 



Soot* 



Sable* 



Dot* 



Bow* 



Lemon* 



Lethal 2 



Cherry 



Fused* 



Forked* 



Shifted* 



Lethal sa. . . . 



Bar 



Notch 



Depressed* . . 

 Lethal sb. . . . 



Club* 



Green* 



Chrome* . . . . 



Lethal 3 



Lethal 3a. . . . 

 Lethal \b*. . . 



Facet* 



Lethal sc . . . . 

 Lethal sd. . . . 

 Furrowed. . . . 



Part affected. 



Eye-color. . . 



Wings 



Wings 



Eye-color. . . 

 Body-color. 

 Abdomen. . . 

 Eye-color. . . 



Wings 



Legs 



Life 



Life 



Body-color . 

 Body-color. 



Thorax 



Wings 



Body-color. 



Life 



Eye-color. . . 

 Venation . . . 

 Bristles. . . . 

 Venation. . . 



Life 



Eye-shape. . 



Wing 



Wing 



Life 



Wings 



Body-color . 

 Body-color. 



Life 



Life 



Life 



Eye 



Life 



Life 



Eye 



Figure. 



II 

 A 



7-8 



lO 



5 

 4 



7-8 

 B 



14-17 



2 



C 



3 



9 

 D 

 E 

 F 



12-13 

 G 

 H 



Symbol 



w 



r 

 m 



V 



y 



A' 



we 

 bi 



ll 



ha 



s 



Im 



I2 



WC 



fu 

 f 



Sh 

 Isa 



B' 



N' 

 dp 



Isb 



Cf 



I3 



ha 

 hb 

 fa 

 Isc 

 Jsd 

 fw 



Locus. 



1 .1 



55-1 

 36.1 



33-0 

 0.0 

 2.4. 

 I.I 

 6.3 



34-7 

 0.7 



3-3 

 0.0 



43 -o 



33 = 



17-5 

 12.5 = 

 1 .1 

 59-5 

 56.5 

 17.8 



23-7 

 S7-0 

 2.6 

 18.0 

 16.7 

 14.6 



26.5 



19s 

 i.i- 



2.2 

 66.2 



38.0 



Date found. 



May 



June 



Aug. 



Nov. 



Jan. 



July 



Aug. 



Nov. 



Nov. 



Feb. 



Mar. 



April 



July 



July 



Aug. 



Aug. 



Sept. 



Oct. 



Nov. 



Nov. 



Jan. 



Jan. 



Feb. 



Mar. 



April 



April 



May 



May 



Sept. 



Dec. 



Jan. 



Feb. 



Feb. 



April 



May 



Nov. 



1910 

 1910 

 1910 

 1910 

 1911 

 1911 

 191 1 

 1911 

 1911 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1912 

 1913 

 1913 

 1913 

 1913 

 1913 

 1913 

 1913 

 1913 

 1913 

 1913 

 1914 

 1914 

 1914 

 1914 

 1914 

 1914 



Found by. 



Morgan. 



Morgan. 



Morgan. 



Morgan. 



Wallace. 



Morgan. 



Morgan. 



Morgan. 



Hoge. 



Rawls. 



Rawls. 



Catteli. 



Bridges. 



Bridges. 



Bridges. 



Wallace. 



Morgan. 



Safir. 



Bridges. 



Bridges. 



Bridges. 



Stark. 



Tice. 



Dexter. 



Bridges. 



Stark. 



Morgan. 



Bridges. 



Bridges. 



Morgan. 



Morgan. 



Morgan. 



Bridges. 



Stark. 



Stark. 



Duncan. 



the zero, with white at i, and with bifid at 6. If we know the cross- 

 over values given by a new mutant with any two mutants of the same 

 chromosome whose positions are already determined, then we can 

 locate the new factor with accuracy, and be able to predict the cross- 

 over value which the new factor will give with any other factor whose 

 position is plotted. 



The factors are located preferably by short distances {i. e.y by those 

 cases in which the amount of crossing-over is small), because when the 

 amount of crossing-over is large a correction must be made for double 

 crossing-over, and the correction can be best found through breaking up 

 the long distances into short ones, by using intermediate points. 



Conversely, when a long distance is indicated on the chromosome 

 diagram, the actual cross-over value found by experiment {i. e., the 



