THE CAMPHOR THRIPS. 11 
HATCHING. 
Hatching has been observed to take place at various times during 
the day, but in the breeding jars the majority of the thrips seem to 
hatch during the morning. When ready to hatch, a lidlike cap splits 
off at the anterior end of the egg, although it remains attached at one 
side. Sometimes also the egg splits longitudinally, enabling the 
young thrips to crawl out more easily. It emerges head first and 
gradually works its way out until it is able to place the front feet on 
the twig. It then easily draws itself out of the eggshell. When free 
the thrips at once crawls away in search of food and pays no attention 
to the empty shell. The entire process of hatching required about 2 
minutes in the case of several individuals observed. The empty egg- 
shell does not collapse, but remains intact on the twig, often for a 
period of several months. 
FIRST-STAGE LARVA. 
The young thrips begin their search for food as soon as they leave 
the eggs and remain active throughout their larval period. They are 
found in cracks and lesions of the bark and on the buds and new ter- 
minal growth. The molt takes place almost anywhere on the limbs 
or leaves. When ready to molt the larva becomes quiescent for a 
short time, after which the skin splits along the dorsum and the larva 
easily liberates itself from the old skin. 
The first instar in summer lasted from 3 to 7 days in the case of 66 
individuals, with an average of 4.05 days. In winter a longer period 
is required, running from 5 to 10 days, with an average of 7.9 
days. Table 2 gives detailed records for the breeding work, the data 
for summer and winter being shown separately. 
SECOND-STAGE LARVA. 
Following the first molt the larvae increase in size rapidly and are more 
conspicuous on the trees, owing to the prominent orange-red coloring. 
The larvae in this stage are also more active and move about rath er 
rapidly, covering considerable areas of the host plant. When disturbed 
they quickly crawl around the limb, seeking a bark lesion for safety, 
or will go down the limb into the interior of the tree. The favorite 
feeding place seems to be on the buds and new terminal shoots, when 
there is any new growth on the trees. On cloudy or rainy days, how- 
ever, or during a period of cold weather the thrips are seldom seen on 
the leaves and shoots, but remain down in the bark lesions, where they 
feed on the cambium layer of the wood. Instances have been noted 
in which they have tunneled back for several inches under the bark or 
in the center of the limb. When ready to molt again, the larvae go 
down under the loose bark or into some crack or lesion, where they 
pass a brief period of inactivity before shedding the larval skin. 
The second stage lasts only slightly longer than the first, but show 
a greater individual variation. As shown in Table 2, it ranged from 3 
to 11 days in summer, with an average of 4.55 days for 59 individuals, 
and in winter from 6 to 11 days, with an average of 7.94 days. 
PREPUPA. 
The prepupal stage is passed largely in some lesion under the bark 
and is of short duration. Although the insects in this sta^e are able 
to crawl, they show little activity and probably feed very little. 
