50 
tion in oviposition was at once apparent. Following are the ovi posi- 
tion records for each night, the time of fertilization being marked b^^ 
the separating vertical line. 
Table XIII. — Effect of fertilization on egg laying. 
Infertile eggs. 
Fertile eggs. 
Moth No. 1 
41 
50 
'si' 
45 
3 
209 
35 
4 
180 
23 
293 
894 
337 
1,570 
71 
122 
619 
227 
27 
200 
150 
26 
40 
36 
20 
33 34 
17 3 
Moth No. 2 
Moth No 3 
CHANGES IX EXTEENAL APPEARANCE. 
The original uniform white color of the egg persists for a period of 
about fifteen hours. At the end of this time the upper third has 
usually acquired a tint which is noticeably more yellowish than the 
rest of the egg. The lower part of this 3'ellowish portion gradually 
darkens until, about thirty hours after the egg is laid, it has become 
reddish or brownish. This brownish color deepens until, at the end 
of thirty-six hours, it is quite distinct, even to the naked eye. The 
outlines of the band are often broken or irregular and an additional 
reddish spot, much less evident than the band, can now usually be 
seen near the micropyle. When about forty hours have elapsed, the 
whole egg has acquired a dull appearance, and the pigmentation of the 
brownish band is also a little deeper. After this the whole egg rapidly 
becomes dusk}" four or five hours before hatching and the brown zone 
is obscured. 
E3IBEYONIC DEVELOPMENT. 
In order to connect the real development of the egg with the series 
of external changes indicating its growth, it may be well to summarize 
briefly the embr3"onic development. 
The egg is fertilized shorth" before it is laid and development begins 
immediately. After about twelve hours the blastoderm is completely 
formed and the beginning of the germ band several hours later causes 
the appearance of the pale brownish ring when the egg is from fifteen 
to eighteen hours old. The development of the embryo and the for- 
mation of the appendages during the next twent3'-four hours are indi- 
cated by the deepening of the color. Finallv, the disposition of- the 
pigment in the chitinous skin and tubercles causes the blackening of 
the egg just previous to hatching. 
HATCHING. 
The head of the fully developed embryo larva is quite plainly to be 
seen through the eggshell, as is also more or less of the coiled body. 
The head is now directly under the microp^'le, and the body of the 
larva extends backward with its dorsal surface pressed against the egg- 
