NORTH AMERICAN COLEOPTERA. 99 



lowing table, the tarsi have greatest length in mfescens and gradually 

 shorten to spissipes, this is also true of the terminal joint of the tar- 

 sus and the claws. In erassa and spissipes the last joint of the hind 

 tarsus is very little longer than the fourth and the claws very small 

 and slender. 



The pygidium is usually entirely covered by the elytra, and there 

 is no median groove such as has been remarked in Atsenius, 



The species are not numerous, but from present appearances our 

 country has a greater number than all elsewhere known. 



At the time of my synopsis (Trans. Am. Ent. Soc. 1871, p. 293) 

 four species were enumerated, three have since been described by 

 Dr. LeConte and two new ones added in the present j)ai)er, one re- 

 mains unknown, although probably identical with lacuMris. 



The form of the posterior tibial spurs made the basis of the sepa- 

 ration of species, the same plan was followed by Dr. LeConte (Proc. 

 Am. Philos. Soc. 187(S, p. BIO). In the following table other char- 

 acters have been used which place the species in a more natural re- 

 lation and sequence, at the same time more easy to comprehend and 

 more certain in the results obtained. 



Thorax with distinct basal marginal line 2. 



Thorax without basal marg;inal line 6. 



2. — Spurs of hind tibiie slender and usually long o. 



Spurs of hind tibise shorter, explanate at tip and with rather broad trans- 

 lucent border -J- 



3.— Form slender, elongate, parallel, rufous rufescoiis. 



Form robust, broader behind 4. 



4. — Species of larger size .16-.22 inch : 4.-5.5 mm. 



Thorax coarsely punctured, rather closely even to the lateral margin. 

 Elytral intervals irregularly biseriately punctulate ; lateral margin of 

 thorax coarsely crenate, the median line po.steriorly distinctly im- 



pres.sed oyliiidric-a. 



Elytral intervals smooth; margin of thorax at uu)st indistinctly cnnale, 



median line not impressed lacuslris. 



Thorax rather finely and sparsely punctured; near the sides, esiiccially at 

 the hind angles quite smooth, the lateral margin entire. 



Itlaiioliiirdi. 



Species of small size .08 inch; 2 mm pusilla. 



5.— Thorax coarsely sparsely punctured, smoother at sides, where the .-surface is 



somewhat irregular: intervals of elytra nearly flat fOiiCerlai. 



6.— Posterior tibi» slender, that is much less than half as broad at apex as long 

 on the posterior edge ; elytral striaj distinctly punctured. 

 Thorax with coarse, sparse punctures everywhere, except a smooth space 



near the hind angles, a small lateral fovea only laliNpiiia. 



Thorax rather closely and more finely i)unctured, smooth at sides, a railier 

 large transverse fovea on the declivity opirox. 



