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. Ent., xvi, 95.) 



AFFECTING THE TRUNK. 



3. The oak carpenter worm. 



Prionoxystua robiniw (Peck). 



Order Lepidoptkra; 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 Kiley. 



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 



