4 Farmers’ Bulletin: 1188. 
time all of the trees that were attacked during the previous fall and 
early winter are dead and abandoned by the beetles. 
From three to five generations occur annually. The first genera- 
tion begins with the eggs deposited by the first beetles that fly and 
attack the trees in the spring and by those of the overwintered 
broods as they make successive attacks during the spring and early 
summer. 
The second generation begins with the eggs deposited by the adults 
of the first generation, and so on until cold weather stops their: 
activities. 
Fic. 1.—Egg galleries .and larval mines of the southern pine ° 
beetle: a, Entrance; 6, entrance burrow; c, egg gallery; 
d, normal larval mine; e, abnormal larval mine; f, terminal ; 
g, ventilating burrows. Slightly reduced. 
At all times there is a more or less complex overlapping of gen- 
erations, so that emergence and attack are continuous during the 
entire period of activity ; consequently, there is a continuous dying of 
trees within the infested areas. 
Under average or normal conditions of the activities of this beetle 
a few scattering trees are killed by it each year in mature stands of 
pine timber throughout the Southern States where the pine is com- 
mon. If, however, from any cause, conditions become favorable 
for the multiplication of the insect, it is able to kill groups of trees, 
and if these groups increase in number and size the following year 
ae Se 
ee ee ee ee 
