AMERICAN COLEOPTERA. 151 



1. P. flavicornis Chapuis, 154.=Bostrichus jfiav. Fabr. &c. 



2. P. compositus Say. Chapuis, 163. 



3. P. tremiferus Chapuis, 174. 



4. P. perfossus Chapuis, 176. 



5. P. rugosus Chapuis, 176. 



6. P. Blanchardi Chapuis, 185. 



7. P. punctulatus Chapuis, 199. 



8. P. disciporus Chapuis, 219. 



9. P. quadridentatus Lee. in Chapuis, 33S.=Sco!ytus 4-dent. Oliv. 



I may add to the brief description of this last named species which I 

 wrote to Dr. Chapuis, that it approaches to, and is perhaps identical with 

 his P. Blaiuhardi ; by an unfortunate clerical or typographical error 

 the two acute tubercles or spines of the abdomen are stated to be on 

 the 3d instead of the 4th ventral segment. The terminal process of the 

 elytra is truncate, with rounded angles in one specimen, and on one 

 side of a second, which is before me, while on the other side of the 

 latter the two cusps mentioned in the description of P. Blanchardi 

 may be seen. I infer, therefore, that they disappear with age. 



Dr. Zimmermann observes of these insects, that they "are found 

 "mostly in pine logs ; they remain commonly about the foot of the 

 "tree, where they make their dwellings; their presence is easily known 

 "by the large heaps of worm-dust, (wurmmehl,) which they, by moving 

 "backwards, push out of their galleries. In South Carolina, where 

 "they occur abundantly, they also fly to the light in houses, on dark 

 "evenings, from March to October." ' 



Tribe II.— ToMiciNi. 

 The occurrence in our fauna of several genera not represented iu 

 the Zimmermann collection, renders necessary a tabular statement of 

 their affinities, which may be thus expressed : 



A. Head not completely covered by the prothorax, partly visible from above ; 

 prothorax not tuberculate in front. 



Club large, flat, not annulated ; funiculus 2-jointed Crypturgus. 



Club smaller, oval, annulated; funiculus 3-jointed Aphanarthrum. 



B. Head completely overhung by the prothorax, which is very convex and tu- 

 berculate in front. 



a. Club of autennjB large, much compressed, transversely annulated on 

 both surfaces; funiculus 1 — 5-jointed Cryphalus. 



b. Club of antennae large, rounded, entirely corneous on one side, circularly 

 annulate on the other, or solid. 



Eyes divided, club solid Xyloterus. 



Eyes emarginate, club annulated Xyleborus. 



c. Club of antenn£E entirely corneous on one side, transversely annulated 

 on the other, the sutures being undulated. 



Elytra deeply excavated at tip, with the margin of the excavation 

 strongly toothed Tomicus. 



