34 
out an irregular cavit}" about the core, and seems especially partial 
to the seeds. 
The insects pass through five larval stages, and increase in size by 
shedding their skins four times to allow for growth. The width of 
the head of the larva in these different stages averages as follows: 
First stage, 0.38 mm.; second stage, 0.55 mm.; third stage, 0.T8 mm.; 
fourth stage, 1.12 mm. ; fifth stage, 1.6 mm. When in the latter part 
of the first stage and the second part of the third stage the larva3 are 
whitish in color, but with the cervical and anal shields black, and 
with blackish spots around the setae. In the later stages the shields 
become brown, and the spots around the hairs are usually indistinct, 
especialh' in the pinkish larvae. 
TIME SPENT IN THE FRUIT. 
Yery few definite observations have been made in regard to the 
time the larva spends inside the fruit. Le Baron gave the time as 
four weeks; Riley, 25 to 30 days; Slingerland, 20 to 30 days; Card, 10 
to 11 days; and Cordley, 16 to 21 daj^s. From the nature of the case 
it is most difficult to get exact data on this point, as there are many 
accidents which may prove fatal to the experiment. On only 5 larvae 
was the writer able to obtain results definite enough to use with any 
degree of confidence. One of these larva? remained in the apple 14 
days, tw^o 18 days, one 21 days, and another 26 days. Professor Gil- 
lette kindh" furnishes some unpublished data on this point, in which 
he finds larvae to have stayed in the fruits 12, 18, 20, and 24 days, 
respectively, with an average of 19 days. The average of all these 
observations is about 20 days. 
PREPAKATTONS FOR LEAVING THE FRUIT. 
When about full grown the larva makes a passagewa}^ to the out- 
side of the fruit. This is usually made toward the side of the apple, 
in a different direction from that from the entrance hole. Rarely 
does the exit passage follow along or consist of the enlarged entrance 
passage. Before the larva has passed outside the outer portion of the 
passage is filled with a block of frass (PI. V, fig. 2, a), or a cap of silk is 
spun over the hole. 
LEAVING THE FRUIT. 
When ready to leave the fruit the larva pushes out this block or 
tears away the cap of silk, crawls out on the surface of the apple, and 
immediate!}" seeks a place in which to spin a cocoon. (PI. V, fig. 2, h.) 
If the apple is upon the tree the larvae will, in by far the greater num- 
ber of cases, crawl from the apple to the twig, from there to the 
branch, and thence down upon the trunk of the tree. Another method, 
which is compa]"atively rare, is that in which the larva lets itself down 
