454 Prof. E. B. Poulton on the sexes of 
Number and _ (Sexes produced. 
Date. | order of eggs M=male; Observations. 
laid. Fr=female. 
June 2. 7 eggs laid, 
order shown 
below. 
Toe F 
Bhs as M 
3 F 
4 F 
Dies Qsciue ss «6 e+ Larva hatched, but died very 
small. 
6 ..| Did not hatch. Probably no 
development took place; egg 
blackened. 
fs RAY pet hl lAns tice wren nt Ditto. ditto. 
Total lu, 3F 
June 3. 1 egg laid. — Larva did not hatch, but was 
apparently fully formed in the 
ege. 
The total number of eggs laid on each successive day 
forms an interesting curve rising to a maximum on the 
second day and declining very rapidly on the fifth. 
The most striking result shown in these tables is the 
remarkable change in the proportion of the sexes on 
different days. Thus on May 25th there were nearly 
twice as many females as males, on May 27th over 
50 per cent. more males, while on May 28th the numbers 
were equal. It is possible that this change in proportion 
may follow some biological law, especially when con- 
sidered in connection with Mr. Jackson’s and Mr. Latter’s 
above-mentioned observations. Itis at any rate enough 
to suggest further observation. At present, however, as 
I learn from Mr. Francis Galton, to whom I have sub- 
mitted the figures, the numbers are not large enough to 
warrant any such conclusion. 
With regard to the succession of the sexes in a series 
of individuals (May 27th, 28th, and June 2nd), the 
arrangement does not appear to differ from that of black 
and white balls drawn successively out of a bag con- 
taining equal numbers of each. But here, too, wider 
observations are required. The arrangement in little 
groups of the same sex may possibly be adapted to 
favour cross-fertilisation. But even in drawing pairs of 
