A SOMATIC MUTATION IN DROSOPHILA MKI.ANOGASTER 



145 



bristles look as thoiij,'!« they were singed by heat (see Fig. 1; Mohr, 

 1922). This striking alteration may accordingly be recognized in 

 every part of the fly, including the wings and the legs, and the distri- 

 bution of singed and non-singed parts in gynandromorphs and mosaics 

 may be mapped with absolute certainty. 



II. THE OCCURRENCE AND DESCRIPTION OF THE 



SOMATIC MUTATION. 

 In making up the black purple curved Ç X Streak curved c^ stock 

 a single male w^as observed (June 11, 1922) which in somatic appea- 



Fig. 1. Camera-lucida drawing of the exceptional male in which the somatic mu- 

 tation occurred. (When found, the wings of the individual had got wet, and espe- 

 ciall}' the distal part of the left wing was somewhat folded. This folding was straigh- 

 tened out in the drawing). 



ranee was very exceptional. All the bristles and hairs on the left 

 half of the body, including the entire dorsal surface of the thorax 



Hereditas IV. 10 



