14 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 



D.funebris: Two papers: Sturtevant (1918), Mohr and Sturtevant (1919). 

 These papers, and certain unpublished data of my own, indicate 

 the existence of at least 5 mutations, in at least three different 

 chromosome pairs. Three of these are probably identical with 

 mutations previously discovered in D. melanogaster ; two of the 

 latter are in the same (the X) chromosome pair, and show a linkage 

 relation similar to but not identical with that shown by the same 

 two genes in D. melanogaster. 



D. hydei: Hyde (1915) recorded a non-sex-linked recessive eye-color in this 

 species. The form had not then been distinguished from D. 

 repleta, and Hyde used that name for it. 



D. imviigrans: Metz and Metz (1915), using the name D. tripunctata, 

 recorded a non-sex-linked recessive venation character. I have 

 found about five mutations in this species, lying in at least three 

 different chromosome pairs. One of them has appeared in two 

 entirely different stocks, caught wild in widely separated localities. 

 (Unpublished data.) 



D. ohscura: I have found a non-sex-linked recessive, "spread" wing (un- 

 published data). Metz (1916) has recorded three mutations in 

 this species — one sex-linked and two not. Mr. D. E. Lancefield 

 has unpublished data on numerous mutations in this species. 



D. repleta: A sex-linked body-color occurs in nature (Sturtevant, 1915). 

 The data published concerning the distribution of this form need 

 revision, as they were based on classifications of material that 

 included D. hydei and D. mulleri, as well as D. repleta. It is 

 certain that the rarer type occurred in New York and in Arkansas ; 

 but all the other records are doubtful. I have more recently 

 obtained two other mutations in this species, but neither of them 

 was favorable for extensive study (unpublished data). 



D. similis: Metz (1916) has studied a non-sex-linked recessive eye-color 

 called "chocolate." 



D. simulans: The first mutant in this species was found in the wild state 

 by Dr. C. W. Metz. I have found about ten others since then; 

 five of these mutants have been crossed with similar mutant 

 races of D. melanogaster, and have thereby been shown to be due 

 to changes in the same genes as in that species. Four of these are 

 in the X chromosomes, and have the same sequence in the two 

 species. Linkage between sex-linked genes, non-disjunction of the 

 sex chromosomes, and gynandromorphism have all been shown to 

 occur here and to be closely similar to the same phenomena in 

 D. melanogaster. All the data on this species are still unpublished. 



D. virilis: Metz (1916, 1917, 1918) has studied this species in some detail. 

 He has reported 16 mutations, 8 of which are sex-linked, and has 

 determined the positions of the latter on the X chromosome. At 

 least three groups of genes are represented. Three of the muta- 

 tions appear to be the same as previously known ones in D. 

 melanogaster. 



D. willistoni: Dr. Metz has unpublished data on a number of mutations in 

 this species, and on their interrelations. 



