228 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
Southern firms shipping export stock to Europe have much trouble 
with these beetles, as the damage is usually hidden until after unload- 
ing and storing for a time in the foreign port. The eggs are laid in 
the pores of the wood, and small-pored woods are seldom attacked. 
Only seasoned wood is attacked, usually that below 15 percent in 
moisture content. LZ. parallelopipedus can complete its life cycle m 
3 months in the extreme South, whereas other species there take from 
9 to 12 months. All species in the North require 1 year under out- 
door conditions. Minthea rugicollis Wikr. is a cosmopolitan species 
introduced into California and New York in mahogany furniture. 
For the control of these beetles see pages 39-42. 
FamMity CERAMBYCIDAE 
THE ROUNDHEADED BORERS 
The roundheaded borers, longicorns, or cerambycids, as they are 
variously called, are very abundant and widely distributed. They 
probably come to the attention of the forester more frequently than 
do representatives of any other group. Thus, aside from their great 
economic importance, they are of much interest as well. 
Primarily they are feeders on dead wood. Their most important 
role in the economy of the forest might be said to be the part they 
play in the disintegration of slash and dead and dying trees. A 
number of forms, however, attack living trees, causing much injury 
or ultimate death. Such forms as Romaleum, Hammoderus and Goes 
in oaks, Saperda and Plectrodera in poplars, and Megacyllene robiniae 
(Forst.) in locusts are examples of this type. 
The roundheaded borers cause serious defects in lumber. Some of 
this injury results from their attack on the living tree, in other cases 
on the recently felled tree before the logs are sawed. Such defects 
cause a reduction in the grade and consequent loss in the value of the 
wood products. This type of injury probably causes a far greater 
monetary loss than that caused by the borers that kill trees. The 
defects in living trees are frequently enlarged by other borers, such 
as Parandra beetles or the carpenter ants, which continue excavating 
until the heartwood is completely destroyed. 
Occasionally great storms sweep through forested regions and blow 
down many thousands of feet of commercial timber. It usually fol- 
lows that certain of these borers attack the fallen trees, totally destroy- 
ing the wood for commercial purposes before it can be utilized. 
The roundheaded borers frequently attack shade trees, particularly 
when other factors, such as defoliation, diseases, drought, frosts, or 
transplanting weaken the trees, making them susceptible to attack. 
Under these circumstances, it is often difficult to place the exact 
responsibility for the ultimate death of the tree. Long experience 
and observation of those wood-boring forms that attack living trees 
lead to the conclusion that the death of the tree is caused by the 
mechanical weakening of the tree by these borers and the resulting 
breakage, in contrast with the bark beetles, which cause the death of 
trees by their initial attack, and the coincident introduction of fungi, 
which cut off the water-conducting tissue of the plant. Occasionally, 
as with the locust borer, particularly in dry seasons, the outer water- 
conducting rings will be completely girdled and the tree killed. 
