64 
THE SCOLYTID BEETLES. 
the past century , to which there are numerous references, was more 
than likely caused by it. It has been more or less active in the States 
south of Virginia, southward to Texas, since 1902, and in some 
localities and during some years it has killed a large amount of timber. 
It is therefore a constant menace to the pine timber of the Southern 
States. 
EVIDENCES OP ATTACK. 
The first external evidence that living trees are being attacked by 
this species is the presence of pitch tubes (fig. 22) on the upper to 
middle trunk, or of reddish boring dust lodged in the loose bark and 
around the base of 
the trees. If the 
attack is sufficient 
to kill the trees, the 
presence of the in- 
sect will be indicat- 
ed in about two 
weeks by the fading 
and yellowish ap- 
pearance of the 
leaves, and in about 
a month after the 
attack the leaves 
will be yellowish to 
reddish, all of the 
bark except that on 
the base of the 
trunks will be dead, 
and the broods of 
the destructive ene- 
my will be ready to 
emerge or will have 
emerged. After 
the leaves have become reddish brown practically all of the broods 
will be out. Positive evidence, however, that the above-described 
external conditions are caused by this beetle is obtained only by 
authentic identification of specimens of the insect or its work taken 
from the affected trees. The presence of the insect in destructive and 
dangerous numbers is indicated by frequent patches of djdng pine or 
spruce during Juty, August, and September, and the sudden death 
of the timber over large areas will indicate a destructive invasion 
requiring prompt and radical measures for its control. 
Fig. 26.— Table Mountain pine, Mineral County, W. Va., seven years 
after it was killed by tbe southern pine beetle. (Original, from 
photograph.) 
