706 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



Length of the body, 26 to SO""™ ; in one 30"°! in length the head is 3 to 4™"" long 

 and C"'" broad ; prothorax 2.3™™ long and 6"'™ broad ; breadth of eighth abdominal 

 segment, 5'""'. 



The cell in which the larva rests during the winter, and in which the pupae and 

 beetles reside, is irregularly oval, about 2 inches long and one-third as wide, very 

 shallow, and partly surrounded by a wide border of closely packed chips gnawed otf 

 from the wood, and partly by the excrement or reddish sawdust-like closely packed 

 material, derived originally from the inner part of tbe bark. The entire cavity is 

 thus about 4 inches long and 2 wide, and very irregularly oval in outline. It seems 

 probable that this larva does not make a regular wavy burrow, but remains in one 

 spot, eating out in all directions from a comparatively fixed point ; in this resi)ect it 

 odiffers from many other Cerambycid larvse. 



38. WOOD-ENGRAVEK BARK-BEETLK. 



Xyleborus coslatus EichhoC (A', xylographus of Fitch.) 



Order Coleoptera ; family Scolytid^. 



(Plate XXIV ; figs. 2, 2b, larva; 3, 3a, pupa.) 



In the outer surface of the sap-wood and inner layers of the bark, mining a long 

 slender thread-like track, usually straight, lengthwise, 4 to 8 inches long, from which 

 numerous smaller short tracks branch off mostly at right angles, a small bark-beetle 

 0.12 long, which comes abroad mostly in May, of a chestnut color, the declivity at 

 the tip of its wing-covers having four or five minute projecting teeth upon each side. 

 (Fitch.) 



This, like other bark beetles, has a compact cylindrical body at least 

 three times as long as broad, with the thorax forming almost half of 

 the entire length, and having the head deeply sunk in its anterior end 

 and almost hid. The antennae are quite small, and are composed of a 

 long basal joint, which becomes thicker towards its tip, and is followed 

 by five very small joints surmounted by a large, round, flattened club, 

 which is divided by sutures into three or four segments. 



This species is glossy and bearded with fine hairs. Its thorax is 

 shagreened anteriorly with minute elevated points, which further back 

 become less dense, and the basal half is covered with fine punctures, 

 with a smooth Hue above along the middle from the center backwards. 

 The wing-covers have rows of coarse punctures and minute ones on the 

 interstices between these rows, and their tips are abruptly declined as 

 though cut or gnawed off, the outer margin of this declivity having 

 four or five small projecting teeth upon each side. It is usually chest- 

 nut colored, with the antennae and legs paler, but individuals may be 

 met with of the varieties mentioned below :* 



*Mr. Schwarz remarks (Ent. Amer., ii, p. 41): A glance at Fitch's description plainly 

 shows that he was mistaken in the identification of the species and that he had be- 

 fore him what is now known as X. cwlatus Eichh. Moreover, X. xylographus belongs 

 to a group of species which do not live under the bark, but enter the solid wood, X. 

 saxeseni Ratz. is said by Eichhoff (/. c, p. 280) to occur in North America, and this 

 could only be identical with X xylograplais. Say's name, however, would have 

 priority. 



Variety a, nigncollis. Thorax black. 



b, niger. Thorax and wing-covers black, 



c, fiilvus. Tliorar and wing-covers pale yellowish. 



