- INSECTS INJURIOUS TO THE OAK. 7 
southward to Texas, oak lumber and cord wood is commonly seen to be 
often honeycombed by the large black burrows of this common and des- 
tructive borer. It is the most directly injurious of all the insects prey- 
ing on this noble tree, since it sinks its tunnels deep in towards the heart 
of the tree in the living wood, and is a difficult insect to discover until 
after the injury is done. It may be found in the autumn and winter 
months, of different sizes, showing that at least there is an interval of 
one year between the smaller and larger sizes, and that consequently 
the moth is two years in attaining maturity. 
The female moth, without doubt, lays her eggs in the eracks and 
interstices of the bark of the oak or locust, in the latitude of Boston, 
about the middle of July. 
I have taken the larvie and chrysalis from the red oak in Maine, and 
the insect occurs westward to the Mississippi Valley and southward to 
Bosque County, Central Texas. At Houston, Texas, I have found adozen 
or more of the cast chrysalid skins projecting from a stump of the pin 
oak; one pupa was alive early in April. It is said by Fitch to be more 
common in the southern and southwestern States than in the northern. It 
is also an inhabitant of California, and may be found to occur in nearly all 
the United States wherever the black, red, and white oak or locust 
trees grow. The habits and metamorphoses of the moth were first dis- 
covered by Peck,* who bred it from caterpillars found in the locust, but 
Harris afterwards discovered that it “‘ perforates the trunks of the red 
oak.” 
The following account of its habits and transformations is copied from . 
Fitch: 
Of all the wood-boring insects in our land this is by far the most pernicious, wound- 
ing the trees the most cruelly. The stateliest oaks in our forests are ruined, probably 
in every instance where one of these borers obtains a lodgment in their trunks. It 
perforates a hole the size of a half-inch auger, or large enough to admit the little 
finger, and requiring three or four years for the bark to close together over it. This 
hole running inward to the heart of the tree, and admitting the water thereto from 
every shower that passes, causes a decay in the wood to commence, and the tree never 
regains its previous soundness. t 
This is also a most prolific insect. The abdomen of the female is so filled and dis- 
tended with eggs that it becomes unwieldy and inert, falling from side to side as its 
position is shifted. A specimen which I once obtained, extruded upwards of three 
hundred eggs within a few hours after its capture, its abdomen becoming diminished 
hereby to nearly half its previous bulk; and in the analogous European species more 
than a thousand eggs have been found on dissection. It hence appears that a single 
one of these insects is capable of ruining a whole forest of oak trees. This calamity, 
however, is prevented, probably by most of the eggs being destroyed, either by birds 
or by other insects, for these borers are by no means so common in our trees as the fecun- 
dity of their parents would lead us to expect. 
Our moth comes abroad, as already stated, in June and the forepart of July. It flies 
only in the night time, remaining at rest during the day, clinging to the trunks of 
_— 
*Mass. Agr. Report and Journal, vol. v, p. 67, with a plate, 1818. 
i We have observed that the old burrows are lined by a dark layer, consisting of a mealy débris about 
as thick as pasteboard; this detritus is probably composed of the castings of the larva, forming a 
paste which in drying strongly adheres to the sides of the gallery.—A. S. P. 
