148 THE SCOLYTID BEETLES. 
or later. Therefore there is a succession of emerging adults through- 
out the greater part of the warm season, and it is not improbable that 
some of them pass the second winter as matured adults. 
GENERATION. 
The broods from eggs of overwintered parent adults evidently de- 
velop into adults, some of which emerge before hibernation begins 
in the fall, but it is probable that most of them pass the winter as 
matured adults. The overwintered broods of adults begin to deposit 
eggs in March and April, and continue to do so as successive broods 
appear until activity ceases in the fall. The eggs begin to hatch in 
March and April, the process continuing during April and May and 
until July or later. The principal active or feeding stage of the 
larvae is during the period from May to July, but this stage may 
occur in any month of the year. The more advanced broods from 
eggs deposited in March evidently transform to pupae and adults in 
July or August, but it appears that the principal period of transfor- 
mation is in the fall, while the broods from eggs deposited in the sum- 
mer do not transform until the following spring. 
It is probable that some of the adults of the earlier broods may 
emerge in the fall, but no good evidence has been found that they 
do so in the northern section of the distribution. There is, however, 
such a complex overlapping of broods that it has been difficult to 
arrive at any conclusions regarding the normal period required for 
the development and emergence of all of the broods of a generation. 
It is evident, however, that in the northern section there is but one 
generation annually, and that in some cases it may require two years 
from the appearance of the earliest broods until all of the latest broods 
have developed and emerged and that, therefore, individuals of one 
generation may pass over two winters, first as young larvae, and second 
as matured adults and larvae, the latter from eggs deposited in the 
spring by the overwintered parent adults. It may also happen, as 
is known in some Curculionidse, that some of the adults may live 
two years or more. 
Southern Section. 
In the region east of central North Carolina and south of western 
North Carolina and eastern Tennessee the seasonal history differs 
from that in the northern section, mainly in the fact that activity 
begins earlier in the spring and continues later in the fall, that in its 
more southern distribution it evidently continues active during the 
entire year, and that there is one complete generation and a par- 
tial second, if not two generations, annually, in the most southern 
localities. 
