14g) 
The assumption follows that the nine-spotted and black phases 
behave as a simple allelomorphic pair. 
HEREDITY OF THE BLACK CROSSED WITH THE NORMAL 
PHASE. 
The inheritance of the black crossed with the normal phase 
was next studied. A black female reared from pair No. 19 
was mated with a normal male of Hawaiian stock as pair 
No. 33. From this mating nineteen normal beetles were reared 
and no black offspring, thus showing that the normal phase is 
dominant over the black. A reciprocal cross No. 34 was also 
made, using a normal female reared from pair No. 27 (parents 
and grandparents for three generations being nine-spotted) and 
a black male from pair No. 20. This mating produced twenty- 
six normal offspring, and thus also showed complete dominance 
of the normal phase. 
The normal offspring of these two crosses were next mated 
together and the following results were obtained: 
Female Male Phase of 
Pair No. from from parents Character of offspring 
38 No.. 33 No. 34 Normal 22 normal, 7 black 
39 No. 33 No. 34 Normal 36 normal, 9 black 
Totals 58 normal, 16 black 
We thus find an approximate Mendelian proportion of the 
black offspring to the more numerous normal beetles, and the 
conclusion is forced upon us that the black and normal phases 
form a simple allelomorphic pair quite the same as the black 
and nine-spotted phase. It would seem better, however, to 
consider the normal and nine-spotted phases taken together as 
forming one unit of the allelomorphic pair, and the black phase 
as the other unit. 
THE HETEROZYGOUS NORMAL PHASE. 
In the F: generation of crosses between the black and 
normal phases about three-fourths of the offspring are normal, 
ot which one-fourth should be pure normal and one-half heter- 
ozygous or carrying both the black and normal factors of 
inheritance. During the course of my experiments I discov- 
