E. J. Allen and E. W. Sexton 355 



animals were found, amongst them one young one with a large patch of 

 the white pigment spread over the dorsum. This is the first record of 

 the appearance of spots. This specimen, a male, became mature in 

 January, 1916, and was mated with six different females, to see if the 

 spots were inheritable, five Red ones from its own stock, one a young 

 one with a similar dorsal patch, and one Hybrid-Black female. 



All the matings gave spots in the F^ generation, the heavy white 

 reticulation appeared in the F^. and again in the ^3 generations together 

 with the No-white mutation. By May 25, 1916, the male's eyes had 

 become "composite" in appearance (cf Fig. 7). It died Oct. 25, 1916. 



In all, it had 339 offspring, 31 of them spotted, 3 dorsal and 1 both 

 dorsal and on the 1st peraeon -segment : in the F^ generation, 185 young, 

 2 with very heavy reticulation, 11 spotted, 2 dorsal : in the ^3 generation, 

 35 young, 9 spotted, 1 with the heavy reticulation as well, 1 No-white 

 on both sides, and 1 No- white on one side. 



The Pure Red stock was again examined on May 5, 1916. 257 

 animals were found, 252 with the normal bright red eyes, 6 of these 

 with dorsal spots, and 10 with lateral spots; 4 others with very dark 

 pigment in many of the ommatidia, and 1 with the red so dilute as to 

 show as pale pink. 



Since then many spotted have been found in this 1914 Red stock. 

 It has now, Nov., 1918, died out. 



2. Appearance of Spots in the Albino Stock. The spots appeared 

 with the Albino mutation, one of the two original Albino females having 

 a long deep streak of white stretching out from the right eye, which, 

 after a moult, became a large spot, as if the white pigment had all 

 collected at the point farthest from the eye. 



The oiher female (see Allen and Sexton, 1917, Plate VII, Fig. 4) mated 

 with two males, one Pure Red, and one Hybrid Black, and had 99 young, 

 of which four were spotted, two dorsally, and one on the 1st peraeon- 

 segment. (The Hybrid Black male, derived from similar ancestry, 

 evidently carried the factor for spots as well, as, when mated with 

 a wild Pure Black female, it had five spotted young — small lateral 

 spots — out of 87 offspring.) 



The spots appeared in all the F2 matings, the Albinos always giving 

 a much larger proportion than the Coloured. 



In the course of experiments designed to determine the laws of 

 inheritance of the colour of the eye, detailed records were kept of all 

 the spots which occurred, and these records made it clear that the 



