286 E, J. ALLEN AND E. W. SEXTON. 
¥.2. GENERATION. ALBINOS. 
In the F, generation the most interesting feature for study is the 
constitution of the albino offspring. These were mated together success- 
fully in fifteen instances, and without exception gave albino young, the 
total number of young examined and recorded being 140. (For an 
example see Plate III, Fig. 1.) One of these young, in addition to having 
no black or red retinal pigment, also lacked the white accessory pig- 
ment and was quite colourless. This specimen is again referred to on 
p. 339.2. In addition to these separate matings, the albino young of IT 
were put together in a jar to breed, producing 15 young, all Albino. 
Two others were mated with albinos from VI, and had 138 young, all 
Albino. 
The albinos may carry either (1) pure black, (2) pure red or (3) both 
black and red. Amongst the F, offspring belonging to this section the 
constitution has been proved in the following cases :— 
(1) Albino carrying pure black. 
One male (II.D.1.k.) mated with a red no-white gave 38 young, 
all black-eyed. 
One male (Brood 1 of III.B.) mated with a red female from the 
same stock (carrying albino) gave 12 black and 4 albino. 
One male (Brood 1 of III.B.) mated in the same way gave 31 
black and 34 albino (Plate III, Fig. 3). 
One female (Brood 1 of III.C.) mated with a red male (IV.W.) 
from the same stock (carrying albino) gave 29 black and 27 
albino. 
(2) Albino carrying red. 
One female (from a brood of female I.G.) mated with a pure red 
male of the same brood gave 12 all red young (Plate III, 
Fig. 4). 
Another similar female (from the same brood as above) mated 
with a male of the same brood (red carrying the factor for 
albino) gave 7 red and 10 albino young (Plate III, Fig. 5). 
(3) Albino carrying black and red. 
One male (II.D.1.].) mated with a red no-white gave 42 black and 
38 red voung (Plate IIT, Fig. 6). 
The original albino female AC was like this. 
