THE CAPRICORN-BEETLES. 
99 
The leaves of the oak are rarely shed before the branch 
falls, and thus serve to break the shock. Branches of five 
or six feet in length and an inch in diameter are thus severed 
O 
by these insects, a kind of pruning that must be injurious to 
the trees, and should be guarded against if possible. By 
collecting the fallen branches in the autumn, and burning 
them before the spring, we prevent development of the 
beetles, while we derive some benefit from the branches as 
fuel. 
It is somewhat remarkable that, while the pine and fir 
tribes rarely suffer to any extent from the depredations of 
caterpillars and other leaf-eating insects, the resinous odor 
of these trees, offensive as it is to such insects, does not 
prevent many kinds of borers from burrowing into and de¬ 
stroying tlieir trunks. Several of the Capricorn-beetles, while 
in the grub state, live only in pine and fir trees, or in timber 
of these kinds of wood. They belong chiefiy to the genus 
Callidium^ a name of unknown or obscure origin. Their 
antennae are of moderate length ; they have a somewhat 
flattened body; the head nods forward, as in Stenocorus ; the 
thorax is broad, nearly circular, and somewhat flattened or 
indented above; and the thighs are very slender next to the 
body, but remarkably thick beyond the middle. The larvae 
are of moderate length, more flattened than the grubs of 
the other Capricorn-beetles, have a very broad and horny 
head, small but po^verful jaws, and are provided wdth six 
extremely small legs. They undermine the bark, and per¬ 
forate the wood in various directions, often doino; immense 
injury to the trees, and to new buildings, in the lumber 
composing which they may happen to be concealed. Their 
burrows are wide and not cylindrical, are very winding, and 
are filled up with a kind of compact sawdust as fast as the 
insects advance. The larva state is said to continue two 
years, during which period the insects cast their skins several 
times. The sides of the body in the pupa are thin-edged, 
and finely notched, and the tail is forked. 
