Heredity of Race-Characters in Silkworm (Bombyx mori) 753 
It is recognized that for absolutely adequate results, fourlarge 
series of matings should have been made in 1906, that is, about 
200 matings of bivolts in Series A’ with a like number of matings 
of univolts in the same series, the same number of matings of 
bivolts in Series D and a like number of matings of univolts in 
the same series. 
The arduous labor connected with the breeding of these insects 
under experimental conditions precludes the possibility of rear- 
ing in all series these large lots unless one has undivided time 
to give to the work and much assistance. It was therefore 
determined as the only practical thing to do, to rear one series 
from year to year in large numbers and to reduce the other lots 
to a minimum. It is hoped that the results thus obtained may 
add somewhat to our knowledge of “laws of inheritance.” 
In pursuance of the above plan, a total of three hundred and sixty 
matings were made in the spring of 1907 in the following three 
series. 
Series E, the 1906 univoltin material that failed to bivolt in 
Series A’ (—1905, —1906), 316 matings. 
Series F, the 1906 univoltin material of Series D, (+1905, 
—1906), 21 matings. 
Series G, the 1906 bivoltin material of Series D( +1905, +1906), 
23 matings. 
The distribution and results of these matings may be tabulated 
as follows (see also “Table of Descent”’): 
TABLE III 
BROOD 
| TOTAL RATIO OF | PERCENTAGE 
| CONDITIONS NUMBER OF | NUMBER OF 
NUMBER OF BIVOLTS TO | OF UNIVOLTS 
OF PARENTS | BIVOLTS UNIVOLTS 
| BROODS UNIVOLTS 
AND LINEAGE 
SITES! Deoaea bison |—04—05—06) 316 32 284 1:9- 
S) Gots Je seue apc |—04+05—06 21 4 17 Ley lpS 
Sipae Gaguonooue —04+05+06 23 7 16 Ls2— 
| 
TIGA lac adios od 4\aboBsocoddor 360 43 317 
