32 E. W. SEXTON AND M. B. WING. 
Black and 67 Red; and N family by 10 broods, 78 young, 62 Black and 
16 Red. 
By this time the animals were beginning to die out. N family was 
finished by June 16, 1915; M family on that date had only 1 male and 
4 females left (this male died on July 22); while K family still had 3 
males and 16 females. 
The next 65 broods (to May 24, 1915) brought the number of young 
extruded to 2000=1505 Black and 495 Red: K family with 1228, 924 
Black and 304 Red; M family with 582, 438 Black and 144 Red; and 
N family with 190, 143 Black and 47 Red. 
The number 3001 was reached on July 24, 1915, total number of Black 
2270, and of Red 731; K family with 1540 Black and 490 Red; 
M family with 552 Black and 181 Red; and N family with 178 Black 
and 60 Red. 
The figures therefore for the second and third thousand give to the 
Blacks a slight excess over the theoretical figure. In the first thousand 
(1004) the proportions, three Black to one Red, were exact; in the 2000 
they were very nearly right; but in the 3000 the Black rather predomi- 
nated, the fact that the Black is the hardier strain probably accounting 
for this. 
This same slight but steady increase can be seen on a small scale in the 
detailed Brood-records of the Hybrid crosses H.R. In the first broods 
of each pair the proportions are nearly always exact, half Black and half 
Red, but the total results for all the broods show a preponderance of 
Black (see lists, p. 35); compare also for an example of a single brood 
Exp. 85, p. 38. 
In Exp. 85 Brood 1 numbered 24 = 12 Black, 12 Red. 
Bag 12 Oia Sie) Wake SOM 
und. DS relate, Mgt a 
4 985-914 nae alae 
Leb 9078s teOoy teri asi 
Gauge: 29, 90% say oO 
Pan * ie See ee Olas 
8 sth Ontaaee Sides 
9 : [4 Sve 6.18 
EEO oe) 26 1 yeu. t aula 
11 ¥ 34 15y Bee 1977 x 
12 2 Np Set ISN Po ie. 
13 mF 26 al ae Aas 
Total .- 13 broods. *°332 176 Black. 156 Red: 
voung, 
