History and Habits of Pityogenes. 13 
three. Thus as a smaller number of egg galleries originated 
from each nuptial chamber there was ieee dikelihood ae many 
of them closely paralleling each other, and consequently 
fewer of the larvae in the cultures died of starvation. In 
nature, egg galleries which are closely parallel are very com- 
mon and the engravings show that under such conditions 
many of the larvae do not survive to reach adult condition. 
Hisernation.— Pityogenes hopkinsi hibernates in either 
the larval, pupal or adult condition. Burrows opened late 
in the fall, early in the spring or during the winter are 
likely to contain any or all of these stages. The author’s 
collections include specimens taken at Syracuse, N. Y., in 
September, October, November, December, March, April and 
May, as well as during the summer sath and while larvae 
and pupae were not present in all of the burrows they were 
to be found in others at the same time. However, by far 
the greater number of individuals pass the winter as young 
adults, next in number are the larvae which are usually more 
than half grown, while but a relatively small number spend 
the winter in the pupal stage. 
In all stages the hibernating insects are exposed upon 
removing the bark although the hibernating burrow appears 
to groove the sapwood rather more deeply than at other 
seasons of the year. This is especially noticeable in the 
ease of the larvae. Normally the young larvae burrow en- 
tirely in the bark, merely touching the surface of the sap- 
wood, and only begin to groove the sapwood when they are 
nearly half grown. When taken in the late fall or 
winter, however, even the half grown larvae are found 
in burrows which are nearly entirely in the sapwood. 
The pupae during the winter months occupy pupal cham- 
bers (Fig. 27) apparently similar in all respects to those 
occupied by them at other seasons of the year. The adults 
pass the winter in feeding burrows in the same tree which 
has served them as larval food. While thev have never been 
found hibernating in a new host, there is no reason for 
believing that they never do so, as at other seasons they 
often feed for several days or even weeks in a new host 
