OAK-BORERS. 



77 



and out of a pile of oak cord-wood in the forest, May 30, under such 

 circumstances as convinced me they prey upon the white oak. They 

 were identified by Dr. Horn. 



Beetle. — Black, 0.25 in length or slightly less, and about a third as broad, somewhat 

 flattened, clothed with fine erect gray hairs; its wing-covers with two distinct 

 slender white bands which do not reach the suture, the anterior one more slender 

 than the hind one and curved; the antennae and slender portions of the legs usually 

 chestnut colored. 



16. The common oak clytus. 



Xylotrechus colonus (Fabr. ). 



Order Coleoptera ; Family Cerambycid^e. 



Larva, with details. Plate XXII, Figs. 2, 2a. 



Mining between the bark and the wood of the oak, up and down the trunk, and 

 making a broad, shallow, irregular groove about 5""'" wide; the larva, pupa, and 

 beetle occurring late in May and early in June. 



I have found, in company with Mr. Calder, the larvae of this pretty 

 beetle in abundance mining under the bark of a fallen (probably white) 



Fig. 26. — Xylotrechus colonus; a, pupa; c, end of body, enlarged; the other figures represent details 

 lab, of the larva, all enlarged; a', antenna; lb, labrum; md, mandible; inx, maxilla with the palpus; 

 labium. — Gissler, del. 



oak, near Providence, May 26; several pupae were also found, one trans- 

 forming to a beetle May 27. The mine extends up and down the trunk, 

 and is of the usual form of longicoru mines, being a broad, shallow, ir- 

 regularly sinuous burrow, and extending part of the way around the 

 trunk, the diameter near the end of the burrow being 5™'".* 



* Larvae of this insect were found February 25, 1882, boring in dry wood of white 

 oak at Washington, D. C. The color of the larviB is pale yellowish or whitish. A 

 yellowish band crosses the pos^terior part of the cervical shield and is beset with 

 short, glistening, backward-directed hairs. The beetles commenced issuing July 3, 

 1882.. (Riley's unpublished notes.) 



