_ INSECTS INJURIOUS TO THE PINE. ~ 165 
eral openings. Thus the mouths of these notches become filled and the 
eggs therein covered and concealed from any predaceous insect which 
may enter the burrow after the parent has completed her work and be- 
fore the eggs have hatched and the young have mined their way beyond 
the reach of such enemies. The female continues her operations until 
her stock of eggs is exhausted, forming a burrow from 4 to 8 inches 
or more in length. 
The eggs of this beetle are about 0.025 long, of a broad, oval shape, 
and a watery white color. They may be met with in their newly formed 
burrows beneath the bark, the fore part of June. They probably hateh 
in ten to twenty days, according to the temperature of the atmosphere. 
at this time. The infantile larva is invariably found lying with its back 
towards the sawdust with which the notch in which it is bred is filled, 
its mouth being thus brought in contact with the soft innermost layer 
of the bark at the extremity of the notch—the elastic nature of the saw- 
dust probably aiding in pressing its mouth against its destined nourish- 
ment. Thus it has only to part its jaws and close them together again 
to fill its mouth with food. And by repetitions of this motion a cavity 
is gradually formed between the bark and the wood, into which its head 
sinks, and afterwards its body. This cavity consequently takes a direc- 
tion outwards at right angles with the central burrow. And thus the 
larva eats its way onward until it has obtained its growth, forming 
hereby a gallery varying in its length from about one to three inches, 
as the material consumed has been of a quality more or less nutritious, 
and winding and turning where impediments have been encountered or 
the track of another larva has been approached. Many of these lateral 
galleries, however, end abruptly before they are half completed, the 
worm having been destroyed by insect enemies or some other casualty. 
And it is curious to notice how these little creatures respect the terri- 
tory which is already in possession of another, changing their course to 
avoid any encroachment thereon; and if one of them finds himself so 
surrounded and hemmed in by other tracks that it becomes impossible 
for him to refrain from encountering them, he so shapes his course as to 
eross his neighbor’s road as nearly as possible at right angles instead 
of obliquely, thus intruding thereon as little and for as short a time as 
possible. Sometimes also two females happen to excavate their galler- 
ies parallel with each other, and so near that no adequate space remains 
between them for their young to mine their burrows, the beetles having 
been unaware of their proximity, no doubt, until too much labor had 
been expended to admit either one to abandon the ground and go else- 
where. In such cases the eggs are all placed along the outer side of 
each gallery, and thus the larve all mine their way outward in opposite 
directions to each other. 
The larva is a plump soft white worm, broadest anteriorly, and with 
its body bent into an arch or having its tail turned partially inward 
under the breast. By transverse impressed lines it is divided into 
