362 SCOLYTID^. 



fLeConte. 



1. C. rigidus, n. sp. 



Dark brown, somewhat shining, of stout cylindrical, somewhat oval 

 form, clothed with rather long erect pale bristles. Prothorax a little wider 

 than long, convex, anterior edge not toothed, disc with a few distant 

 acute tubercles in front of the middle, sparsely punctured behind. Elytra 

 punctured in rows, setigerous punctures of the interspaces very small. 

 Legs and antennae yellow-brown ; club oval, hairy, sutures curved, sur- 

 face rather shining. Length 1 mm. ; .04 inch. 



(^. Front with a small rounded polislied excavation. 



Canada, five specimens. Dr. Horn. This species does not agree very 

 satisfactorily with the descriptions of European authors, and I therefore 

 venture to describe it as new. 



2. C. striatulus Mann. Bull. Mosc, 1853, 235, Alaska, and 



3. O. robustus Eichhoff, Berl. Ent. Zeitschr., 1871, 131, Am. how". 

 are unknown to me. 



Group. IV. Tomioi. 



The species of this group are of cj'lindrical, but not very slender form, 

 and are easily recognized by the deeply excavated elytral declivity, which 

 is sharply margined and acutely toothed. The club of the antennae, as in 

 the group Xylehori, is entirely corneous on the inner face, but is not ob- 

 liquely truncate on the outer face. The sensitive surface is more or less 

 distinctly defined, and is divided by two sutures which are more or le.ss 

 curved or angulated in our species, but are described in some European 

 species as straight, thus showing an affiliation with Dryocates of the prece- 

 ding group. The tibiae are coarsely serrate, and the tarsal joints 1-3 are 

 rather stouter than in the preceding groups. 



Our species represent but one genus, which may be divided conveniently 

 according to the form of the sutures of the antennal club. 



TOMIOUS Latr. 



Sutures of antennal club strongly angulated 2. 



First suture of club nearly straight, second bi- 



sinuate 3. 



Sutures of club nearly straight 8. 



Sutures of club regularly curved, not angulated . . 9. 



2. Margin of declivity with three teeth behind the 



most prominent one 1. calligraphus. 



Margin of declivity with two teeth behind the 

 most prominent one, punctures and inter- 

 spaces regular 2. cacographus. 



Margin of declivity with two teeth behind the 

 most prominent one, punctures and inter- 

 spaces confused 3. confusus. 



Margin of declivity with but one tooth behind the 



most prominent one 4. plastographus. 



