’ 
28 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
The number of mines per leaf at this time averaged from 15 to 18. | 
By August 4 pup had largely yielded moths, and eggs were 
again very abundant, a few having already hatched. By August 26 — 
another generation of moths had developed and their eggs were in ; 
an advanced condition of development and many had already hatched. 4 
September 10 larve of this, the fourth generation, were of various — 
sizes, from quite small to full-grown, but no pup could be found. — 
The leaves, although practically covered with the mines on their 
upper surfaces, were still hanging on the trees, and there was but 
little evidence of serious injury having been done. By October 30 
quite 50 per cent of the foliage was on the ground and those leaves 
remaining on the trees were more or less rolled in from the edges. 
This premature falling of the foliage was undoubtedly due to the 
work of the leaf-miner, and this seems to have been its principal 
injury. At this time the larve were full-grown and had lined their — 
mines with a dense lining of silvery-white silk preparatory to hiber- 
nation. Leaves picked from the ground contained from 6 to 15_ 
larve per leaf. Leaves examined December 6 showed no change of — 
condition, no pupe whatever being found, and this condition was also — 
found to obtain on January 21. March 12 a quantity of leaves were 
collected from the ground, and at this time fully 90 per cent of the ~ 
larve had transformed to pupeze, though this stage had but recently 
been entered, as indicated by the bright-green color. On April 22, — 
at which time the fohage of the apple was just pushing out, only 
pupz could be found, and some of these were quite dark in color, the © 
inclosed moth evidently being nearly developed and ready to escape. 
The formation of pup as just mentioned is perhaps to be regarded 
as abnormally early, since the weather about this time was unusually 
warm. This belief is strengthened by the fact that in infested apple © 
leaves kept in a breeding cage out of doors in the insectary yard the © 
insects were all in the larval condition, except one pupa, on April 
5, the moths mostly emerging the latter part of that month. By May 
7 eggs were very abundant on the foliage of the apple tree under 
observation, as many as 12 being counted on a single leaf, but on 
some leaves none at all were to be seen. At this date no larvee had yet 
hatched, though many eggs were in an advanced stage of development, 
the embryo being readily seen within the delicate shell when examined | 
with a hand lens. By June 24 larve from these eggs had mostly _ 
matured and had entered the pupal stage, though a few full-grown | 
larve were still to be found. The time of maturing of the first — 
generation in 1906, therefore, agrees closely with this period in 1905. — 
Length of life cycle.-—Eggs deposited during the night of July 31 | 
were very generally hatching on the morning of August 8. The- 
larva leaves the egg by eating directly through the lower surface at 
one end into the leaf beneath, at once beginning its mine, and is thus » 
