132 THE SECOND-CHROMOSOME GROUP 



Table 5.— Pi, speck olive 9 X black d"; Fi wild-type 9 + Fi mid-type cf . 



There was confusion in the classification of the oHve in these crosses 

 of olive to black, since flies heterozygous for black are intermediate 

 and were often classified as olive. 



LOCUS OF SPECK. 



At this time it was known that the genes black, purple, vestigial, and 

 curved were in the second chromosome alined in the order named 

 (Morgan and Lynch, 1912; Morgan, 1912; Bridges and Sturtevant, 

 1914). A position for speck still further to the right was indicated 

 by the cross-over values of table 6. Since this eariier work was 



Table 6. — Data upon the crossing over of speck with other second-chromosome 

 genes, summarized from Sturtevant, 1915. 



Table 7. — Pi, purple curved speck cf X wild 9 ; B. C, Pi mid-type 9 X 



purple curved speck c^ from stock. 



if 



m 



