NOTES AND LITERATURE 



MUTATIONS IN DROSOPIIILA BUSCKII COQ.^ 



Two mutations in eye color have appeared in my cultures of 

 Drosophila husckii. These mutations are of especial interest in 

 that, as far as the writer has been able to learn, they are the first 

 that have been recorded in this species. This is the eighth 

 species of Drosophila in which mutations have been recorded, 

 the other seven being ampelophila, repleta, confusa, tripunctata, 

 virilis, ohsciira, and similis. 



The eye mutant which is brighter than normal has been called 

 "red" and the other which is darker than normal has been called 

 ' ' chocolate. ' ' The normal eye of this species is darker than that 

 of Drosophila ampelophila. The mutant red corresponds very 

 closely to the normal eye color of ampelophila except that it is 

 slightly brighter. Ridgeway's "scarlet" (Plate I, color num- 

 ber 5, Ridgeway's Color Standards and Nomenclature, 1912) 

 corresponds most nearly to the eye color of this mutant. In 

 the red eye the ctMitral t1(H-k shows as a small round point, while 

 in the normal hiischi! i'\ e. it ajiptMi-s hu-«rer and le^ definite 

 in shape. Tho I'od eye (hnkons with auv and closely approaches 

 the normal eye iu color, Init at its darkest stage it can be dis- 

 tinguished from the normal in that it is less translucent. The 

 chocolate eye is an opaque brown and presents none of the shiny 

 appearance of the normal eye. The central fleck is invisible in 

 newly emerged flies, but becomes more or less distinct as the fly 

 ages. AYith age the color approaches normal, but always remains 

 slightly darker. Flies over forty-eight hours old so nearly ap- 

 proach normal that they are difficult to distinguish. A newly 

 emerged chocolate corresponds most nearly to Ridgeway's 

 "chestnut brown" (Plate XIV, color number 11, tone m). 



The mutation red eye was first observed in November, 1916, 

 and it seems probable that the original mutation occurred some- 

 what earlier and was overlooked as several red-eyed flies, both 

 males and females, were obtained from this cross. The original 

 stock had been collected about a month earlier in a tomato patch 



1 From the Zoological Laboratory of Indiana University, Contribution 

 No. 157. 



