OAK-BORERS. 
53 
in a very few minutes. Oak Hill can not boast of a balm-of-Gilead or a Lombardy pop- 
lar, but it is famous for its oaks, and while it is admitted that the former trees, as 
mentioned by Harris, serve as food for the larvae, my observations indisputably prove 
that they feed also upon the roots of the oak. (Can. Eat., xvi, 95.) 
AFFECTING THE TRUNK. 
3. The oak carpenter worm. 
Prionoxystus robinice (Peck). 
Order Lepidoptera; Family Cossid^e. 
Boring large holes and galleries in the trunk ; a large, livid, reddish caterpillar, 
nearly three inches long, greenish beneath, and the head shining black ; the body 
somewhat flattened, and with scattered long, fine hairs. The chrysalis also in the 
burrow, and transforming to a large, thick-bodied moth in June and July. 
In different parts of New England, from Maine to Rhode Island, and 
southward to Texas, oak lumber and cord- wood is commonly seen to be 
often honeycombed by the large black burrows of this common and 
destructive borer. It is the most directly injurious of all the insects 
preying 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, and probably three years in attaining 
maturity. 
Fig. 14.— Larva and pupa of female, and male imago of Oak Carpenter Worm— all natural size. 
After Riley. 
The female moth, without doubt, lays her eggs in the cracks and 
interstices of the bark of the oak or locust, in the latitude of Boston, 
about the middle of July. 
I have taken the larva 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, Tex., I have found a dozen 
