NO. 10 MORPHOLOGY OF GNATHOTRICHUS SCIIEDL 7 



of the same diameter as the transverse one extended upwards and two 

 downwards, as shown in the figure, all of the same length, each one 

 having been excavated probably by a single larva. The gallery of our 

 insect thus differs widely from that of the European species {T. eurygaster 

 Erichson) which mines in the interior of the pine, which has no lateral 

 burrows branching off from it. 



The presence of these timber beetles in the wood can be distinguished from 

 those which mine under the hark, by the little piles of sawdust which they 

 throw out at the mouth of their burrows, this dust being so much more 

 white and clean, and not composed in part of the brown or rust-colored 

 particles of gnawed bark which are intermixed with the dust produced by 

 the bark-beetles. 



In addition to the short description of this beetle which is given above, it 

 may be observed that the head is finely punctured, the punctures on the 

 face giving out small pale yellowish hairs, whilst those on the vertex or 

 crown are destitute of hairs, and there is a slight transverse elevation of 

 the surface between the face and the vertex, from which an elevated 

 smooth line extends backwards along the middle of the vertex. Thorax, 

 when viewed from above, with its base transverse and rectilinear, its basal 

 angles rectangular, its opposite sides parallel for a distance equalling the 

 length of the base, and from thence rounded in a semicircle at its anterior 

 end; its surface anteriorly with minute asperities, which, viewed vertically, 

 appear like fine transverse wrinkles ; its basal half with very minute punc- 

 tures, and in its center a small transverse tubercle. Wing covers with 

 fine shallow punctures in rows ; the upper part of the apical declivity 

 moderately depressed in the middle, producing a slight concavity in its 

 outline when viewed from above anteriorly, the suture not elevated in 

 this depression, but showing a slightly impressed line along each side ; the 

 hind end bearded with hairs similar to those upon the front. Under side 

 black, the legs and antennae pale dull yellow. 



1868. Zimmerman, C.(4). 



In the " Synopsis of the Scolytidae of America North of Mexico " 

 the author placed uiatcriar'uts Fitch in Cryptnrgus Erich. Dis- 

 tribution : North Carolina, and from Maine to Canada. 



1868. ElCHHOFF, W.(3). 



Ciiathotrichus corthyloides^ : Valde elongatus, cylindricus, subopacus piceus, 

 elytris basi dilutioribus, antennis pedibusque ferrugineis, thorace elongato 

 cylindrico, antice asperato, disco subnodoso, postice omnium subtilissime 

 vage punctulato, elytris subtiliter transversim aciculatis, subtilissime seri- 

 atim punctatis, declivitate postica convexiuscula, utrinque nodulo longitu- 

 dinali a sutura remoto ornata. Long. 1^/3 Lin. Patria: America bore- 



alis, Carolina. 



' " Ich vermuthe, dass Gn. corthyloides m. identisch ist mit Crypturgtis 

 viateriarins ^= Tomicus materiarius Fitch (Noxious Ins. New York II. No. 24, 

 246), in der soeben von Mr. Leconte zum Geschenk erhaltenen ' Synopsis of the 

 Scolytidae of America North of Mexico.' " 



