ADDITIONAL MUTANT CHARACTERS IN 

 DROSOPHILA WILLISTONI 



Ruth M. Ferry. Rebecca C. Lancefield and Charles W. Metz 

 Dcpartuiciit of Ccnctics, Car)ir</ie Institution of ]Vasliiu(jton 



TWENTY-EIGHT of the sex- 

 linked characters in DrosopJiila 

 Willistoni, Sturt., have heen de- 

 scribed in an earlier paper by Lance- 

 field and Aletz."* The present paper in- 

 cludes descriptions of six additional 

 sex-linked characters and twenty-three 

 autosomal characters in this species. 

 Accompanying each description is an 

 account of the origin of the character 

 and a comparison with similar char- 

 acters in other species, wherever such 

 characters are known. The linkage 

 data, and a comparison of the genetic 

 behavior of the characters with that of 

 characters in other species, will be con- 

 sidered in a subsequent paper. 



A list of the characters together with 

 a brief statement as to their origin and 

 nature are given in Table L In this 

 table the characters are arranged 

 chronologically. In the subsequent de- 

 scriptions the arrangement is chrono- 

 logical within the respective linkage 

 groups, and in the section on characters 

 not yet "placed." 



The present mutant characters as 

 well as those previously described have 

 all arisen in a single line of flies de- 

 rived originally from Cuba. Since the 

 species does not occur in the United 

 States, save rarely in Florida or adja- 

 cent regions, it is practically certain 

 that no contamination of the stocks 

 from outside sources has occurred. f 



We are indebted to Miss E. M. 

 Wallace for making the drawing of 

 tardigrade, and to Miss E. M. Lord for 

 assistance in making the accompanying- 

 photographs, and also for the other 

 drawings. 



Sex-Linked Characters 



lutcvruptcd (/') 

 Figure 15, No. 4 



Description. — Interrupted is a vari- 

 able character distinguished by a break 

 in the fourth vein of the wing, involv- 

 ing the loss of a small section at or 

 near the apex. The character is par- 

 tially sex-limited, appearing fairly 

 regularly in the females, but only occa- 

 sionally in the males. 



Orifjin. — (W1214). One male was 

 found in a mating for short. 



Bald (bd). 

 Figure 19 



Description. — The bristles and hairs 

 on the head are either very small, or 

 entirely missing, in bald. One or all 

 of the dorso-central bristles may be 

 missing and the hairs on the thorax are 

 more sparse than usual and the rows 

 are irregular. Sometimes one, or both, 

 of the anterior scutellar bristles may be 

 small or missing entirely. The most 

 constant characteristic of bald is its 

 efifect on the head bristles and hairs. 



Origin. — (R78^)). One male was 

 found in rounded stock. 



Vermilion (v). 



Description. — Vermilion afifects the 

 color of the eyes, causing them to be 

 a lighter and brighter red than usual. 

 The black fleck in the center of the 

 eye. characteristic of the normal condi- 

 tion, is missing in vermilion, and the 

 ocelli are white rather than yellow. 



Origin. — (RlO?-i). One male was 

 found among the ofif spring of a mating 

 of blunt approximated by blistered. 



*For Numbered References, see "Literature Cited" at end of article. 



fParticular mention is made of this fact, only because the opinion is still held 'n\ some 

 quarters (cf. Hagedoorn and Hagedoorn '22)'' that DrosoptiUa "mutants" may merely be 

 segregates resulting from hybridization. 



373 



