452 Prof. E. B. Poulton on the sexes of 
by the same individual produce now a preponderance of 
one sex, and now of another. Hither of these alterna- 
tives would appear strongly to favour intercrossing. The 
following observations, so far as they go, tend to support 
the latter alternative. 
A pair of Smerinthus populi were found in coitw in an 
Oxford garden, between 10 and 11 a.m., on May 25th, 
1893. They were carefully removed, and remained 
together until 8.40 p.m. The attempt was made to 
observe the order in which the eggs were laid, and to 
rear the larve separately, the sexes being determined 
in the pupal state. The results are most concisely shown 
in a tabular statement. 
Number and |Sexes produced. 
Date. | order of eggs M=male ; Observations. 
laid. r=female. 
May 25. | 44 eggs laid, 15 u 1 missing (unknown whether 
order unnoted. 28 F the egg hatched). 1 male and 
1 female moth emerged in the 
hot summer of 1893. 1 male 
pupa was deformed and dead. 
May 26. | 47 eggs laid. — All these eggs, the order of 
which had been carefully noted, 
hatched during my absence 
from home, and the larve were 
lost. 
May 27. | 34 eggs laid. 4 missing; 1 larva died. 1 
The order of female moth emerged 1893. 1 
the first 22 un- 9M male pupa was deformed and 
noted. 8F dead, and another rather de- 
formed. 
2d 00 oe — Larva died small (probably 
3rd stage). 
24 M Pupa rather deformed. 
25 F 
26 M 
27 S Go HE 
28 - M 
29 M 
30 M 
31 F 
32 1 
38) oc M 
34 M Moth emerged 1893. 
Total 17m, 11¥F 
