INHERITANCE OF ABNORMAL VENATION. 
17 
It will be convenient in the present discussion to adopt the following 
symbols: A: denotes a fly that is abnormal in one wing only; Az, a fly 
abnormal in both wings, and C. S. 
(coefficient of symmetry) that per- 
centage of a given lot of abnormal 
flies which are abnormal in both 
wings. Tables 20 and 21 may be 
summarized as follows: Flies which 
are so abnormal that both wings are 
affected not only gave, on the aver- 
age, a greater percentage of abnor- 
mal offspring than flies abnormal in 
TABLE 20.—Relation between degree of 
abnormality in parents and percent- 
age of abnormal offspring. 
| P. ct. of | 
P. ct. of 
Parents. | abnormal | Parents. | abnormal 
offspring. | offspring. 
aaret 
|} AX A,| 85.1 || NXA,] 45.8 
Ae SN POEe il NS Anes cane tl 
HA OAL Pee NXN 13.8 
| 
| 
| 
only one wing, but the abnormal offspring of the former were more 
It must 
TABLE 21.—Relation between parents and offspring with respect to one wing or both 
being abnormal. 
likely to be abnormal in both wings than those of the latter. 
Parents. Offspring. | Parents. Offspring, 
Male. |Female.| A; Pe eccoeaall iMatens leeraatesy uae Ae C8 
| 
sake 2 |. a Pees Dll wba aera 
A, A | 268.) 1271 |) 0:83 || A; N 55 61 | 0.53 
A, A, 102 178 OGY NEO A, 122 198 0.62 
As N 105 118 0.52. | ING (3 AS 57 53 0.48 
A, A, | 149 | 428 | 0.74 || N N 285 | 160 | 0.36 
Ay A, | 83 158 0.66 | 
be noted that this was only “‘on the average.’’ Although it was an 
exceptional case, we have seen that all the offspring of mating 405 
were normal. The parents each had 
“sreat’’ abnormality in both wings 
From table 22 it seems evident 
that a given asymmetry (abnormal 
in the right wing only or abnormal 
in the left wing only) is not inher- 
ited. The offspring of a parent 
which is abnormal in the left wing 
only are as likely to be abnormal in 
the right as in the left wing, and 
vice versa. This is in accord with the 
results obtained by Castle (1906a) 
for polydactylism of guinea-pigs, 
Larrabee (1906) for the reversed 
optic chiasma of fishes, and Priz- 
bram (1907) for eye-color of cats. 
As was pointed out, all attempts 
to fix any particular form of ahnor- 
TABLE 22. —Relation between parents and 
offspring with respect to which wing 
as abnormal. 
{Ag=Abnormal in right wing only; A.=Abnor- 
mal in left wing only; 
A»,=Abnormal in 
both wings; A,;=Abnormal in one wing 
only.] 
Offspring. 
Parents. —— = = 
eee Sa Wes ei Ns 
aif fist eli Ha. = 
Pg SNe | ATC ARI: QR TOS| 
A,X A, | -.58 |) 79 | —O-16 
AL BB Ger! S0to8 
A,X Ar 36 41 —0.06 | 
A,X Ay 30 25 | +0.09 
A.X Ar 23 24 | —0.02 
Ni S@AR | Zoe! Let 0.28 
BSAC | S71) <2arilet ote 
N XN 146 | 139; -+0.02 
N XA, | 121] 106| +0.07 | 
mality by selection and inbreeding (pure lines?) have failed; nor has 
