12 
The time elapsing between the emergence of the moth and the depo- 
sition of eggs in the cages has varied between | and 9 days, with an 
average of 6.7 days. 
The number of eggs laid in confinement has varied between 2 and 
50, and nearly every one has hatched except where males were not 
confined with the female. Of 65 eggs inelosed in paper sacks upon 
the trees only 2 failed to hatch. | Nearly all the eggs seem to be fertile 
‘at Fort Collins, but at the same time there are many more eggshells 
to be found upon the apples than worm holes in them, which would 
indicate a large mortality among the small worms. Jn our counts we 
have found nearly 90 per cent of these eggs upon the free surface of 
the apples and the remainder upon the leaves. 
CHANGES IN THE EGG DURING INCUBATION. 
When the egg is first laid it is of a pearly white color. Later 
there appears upon it a faint red ring, marking the position of the 
forming embryo. <A day later this ring becomes more distinct and 
later disappears, and in its stead there is a dark central spot, produced 
by the black head and cervical shield of the embryo. When the larve 
leaves the egg the remaining shell appears like a fresh egg, except 
that it is very flat and along one side the slit from which the larva 
made its exit can usually be seen. Notes by an assistant, Mr. E. P. 
Taylor, upon 57 freshly laid eggs show that the red ring appears upon 
the second or third day after the egg is laid, the disappearance of the 
ring and the appearance of the dark spot 2 to 3 days later, and the 
hatching of the egg on the first or second day after the appearance of 
the dark spot. These eggs were deposited in the breeding cages. 
Eggs observed in the orchard required about 1 day more to hateh, 
probably on account of the lower temperature during night, making 
the average incubation period 7 and a fraction days. Riley gave this 
period as from 4 to 10 days, Washburn as 5 to 10 days, and Slinger- 
land as about a week. We have found the time to vary between 6 
and 8 days in the laboratory where the temperature ranged between 
68° during the night and 75° during the middle of the day. For eggs 
kept in a greenhouse where the temperature ran to 110° during the 
middle of the day, the hatching period was 6 days. The records of 
the hatching of eggs in these two rooms is as follows: 
TABLE II1.—Comparison of egg-hatching records in a cool and a hot room. 
1 yy & ( 
Cool room; temper- | Hot room in green- 
ature, between 68° | house; tempera- 
| and 75° F. ture,110° at midday. 
INDUINDOMOL OP RS if a045 2s. aceee aes hace eee eens LD Socata tee ae aee 15. 
Big os lajig! ce Se Aa ee ae es eee ee oe Aug. 11 (night) ---_-- Aug. 11 (night). 
Distmotredwrings ssh Se ee ee eee Angvis.ses.c 5 Aug. 14. 
Dari Centereach san cane eae tac eee eee 2. 22) | A es Aug. 16. 
Hatched) <s2-28e 2-3 oe vai ee ae oe ee ee ee Aug. 18 (morning) -- Aug. 17 (evening). 
Eleven eggs hatched in each of the above lots, the difference in 
time being from evening one day to morning of the next. The time 
