THE SOUTHERN PINE SAWYER. 49 



of the female. In the male this segment shows merely the anal open- 

 ing. In the female two globular tubercles are borne side by side on 

 this segment. 



SEASONAL HISTORY. 



There are four stages in the life of the sawyer, first, the egg (fig 15) • 

 second the larva (fig. 16); third, the pupa (fig. 17); fourth, the 

 adult (fig. 14). 



In southern Mississippi the egg-laying period lasts from about the 

 first of March to the middle of October. In some cases eggs may 

 be laid eariier or later than the dates given, but the main activity in 

 egg-laying will be found to be comprised within this period. The 

 young larvae hatch from the eggs in about five days after the eggs are 

 deposited.'' 



^ The length of time from the hatching of the young larva to the 



time of maturity and change to the pupa appears to vary considerably 



in different individuals. The comparative periods of time spent 



in the larval and pupal stages are not known. However, it is probable 



that while the larval period may last for several months the pupal 



period is not longer than two or three weeks. The length of time 



occupied in passing from the egg to, the adult stage varies greatly 



in different individuals. It appears that normally there is one 



generation a year, with a partial second generation. Thus, on 



August 12, 1908, the writer found larva, pupae, and emergence 



holes in the trunk of a tree which had been felled by storm April 24, 



1908. The fact that the tree was felled on this date makes it certain 



that the eggs of the sawyer were deposited subsequently. This 



gives' us a period of less than four months for the development 



from the egg to the emerged adult, in some individuals. Returning 



to the same tree October 6, 1908, more emergence holes were found, 



but there were still plenty of larvae in the trunk. Also, scattering 



emergence holes were common at this date in other trees felled by 



the storm of April 24, 1908, which were also abundantly infested 



with larvae. On March 19, 1909, the writer again visited the tree 



just mentioned, and found a good many larvae and one pupa still 



in the log. Thus it is seen what a great variation in the length of 



time taken for development there may be among different individuals 



in the same log. The case of the sawyer in the Southern States 



appears to be somewhat analogous to that of certain species of 



Lepidoptera, a few adults of which emerge in the fall, while the 



greater number, of the pupae go through the winter before changing 



o This statement is based upon observations made during the hottest part of the 

 summer. Possibly eggs laid in the spring or fall might not hatch so quickly, as there 

 would be less heat at those periods. 



