OAK-BORERS. 6 1 



It will be seen by the form of this singular borer that it is adapted for 

 a life under or next to the bark of diseased trees, as it is quite unfitted, 

 by reason of the enormously swollen front rings of the body, for boring 

 very far into the living fresh wood, as is the case with the oak-boring cat- 

 erpillar of Prionoxystus robinice, or the oak pruner {Elapliidion villosum). 

 With its short, powerful jaws it can eat its way on either side in front 

 of it, after hatching from the egg, which is probably laid by the parent 

 beetle in some crack in the bark. Its head is rather small and partly 

 sunken within the segment next behind the head. This segment, des- 

 tined to be the prothorax of the beetle, is remarkably broad, nearly 

 three times as much so as the hinder segments, and fully as broad again 

 as it is long, while the surface above is flat and more or less rough or 

 pitted in the middle. With this unusual form it can eat its way in a 

 serpentine course under the bark, deriving its nourishment from the 

 sap-wood next to the bark. Owing to the form of its body in front, 

 the burrow is shallow and broad, in transverse outline oval cylindrical. 

 The body of this as well as most other borers is provided with fine, 

 delicate, scattered hairs, projecting on each side of each segment. 

 Judging by analogy, these hairs are probably provided each with a fine 

 nerve (though this remains to be proved), and probably are endowed 

 with a delicate sense of touch, useful to the insect as it moves to and 

 fro in its gallery. The Buprestid larvae are blind, without simple eyes, 

 since living as they do in total darkness and never coming to the light 

 they do not need even the simple eyes present in many other larvae, 

 and which are probably chiefly of use in enabling the insect to distin- 

 tinguish light from darkness. 



The larvae of the Buprestidce and the breeding habits of the beetles 

 have not as yet been carefully studied in America, and for any exact 

 knowledge we have to go to French and German authors. 



According to Perris, the Buprestids couple in the usual manner, the 

 male mounting ui^on the back of the female, the act of copulation not 

 being of long duration. 



The form of the eggs and their size in our species are unknown, or 

 have not been stated in print. It is most probable that the female lays 

 them in the bottom of cracks in the bark, or under the partly loosened 

 bark at least, where the larva upon hatching may find itself next to or im- 

 mediately in contact with the bast or the sap-wood, which probably forms 

 the greater part of its food, though Ratzeburg has found that the " frass" 

 or excrement is colored by the bark, which indicates that the larvae feed 

 both on the bast and bark. As to the number of eggs laid by the female 

 we have no information. The eggs are deposited in fissures or cracks 

 by means of the extensile end of the body. As Westwood states, ''The 

 abdomen appears to be composed of only five segments; the remainder 

 are, however, internal, and constitute in the female a retractile, corneous, 

 conical plate, employed for depositing theeggs in the chinks of the bark 

 of trees within which the larvae feed." Perris, however, says that "the 



