Heredity of Race-Characters in Silkworm (Bombyx mort) 749 
with others of its kind from a lot of univoltin eggs received from 
Padua, Italy, through Professor Kellogg of Stanford University 
from the director of the Royal Silk-culture Station. The male 
parent was a white cocooner from an unbanded whitish but 
strongly patterned larva of the Japanese bivoltin race. At the 
time the mating was made, the male was selected for its larval 
and cocoon character and its bivoltin character was unknown. 
This was learned later through Prof. Woodworth of the University 
of California from whom the cocoons had been obtained. 
The 230 larvz reared in the spring of 1905 from this 1904 cross 
were all banded and all strongly patterned. Thus the color 
character of the brood partook in toto of the color pattern of each 
parent. The cocoons spun by these larvz were neither salmon 
(the female cocoon color) nor white (the male cocoon color) but 
a grade between the two. ‘They were a shade of light yellow that 
might be termed a blend. For the most part the color was uni- 
form, but in several (comparatively few) individuals it approached 
more nearly to that of the female parent. 
These cocoons are now deposited, with cocoons of parental 
broods, in the museum of the Department of Entomology and 
Bionomics of Stanford University. 
‘We can say therefore of this first cross that neither the larval 
“color and pattern” character nor cocoon color of either parent 
is exclusively dominant in the first generation. The characters 
may be said to have equal potency in this generation. 
The brood however as a whole followed the racial character of 
its female parent in regard to its voltinism (if I may use this 
term to express the number of generations destined to be produced 
in a year). ‘That is, the brood was unzvoltin in the first gen ra- 
tion (1904). I will designate this first generation brood as hybrid 
uni(bi)voltin, indicating that univoltinism is expressed and bivol- 
tinism is not expressed. In later broods where bivoltinism is 
expressed and univoltinism not expressed, the broods will be 
referred to as hybrid bi(uni)voltin. 
From this isolated cross one could not say whether this was a 
case of “dominance” of univoltinism in a Mendelian sense, pre- 
potency of the female parent or prepotency of the univoltin char- 
