402 CLASSIFICATION OF THE CARABID.E 



obtuse, and not at all rounded. The last joint of the maxillary palpi in Blethisa is rela- 

 tively so much shorter than in Elaphrus, that I cannot agree with Brulle and Erichson in 

 uniting the two genera. 



Elaphrus Fabr, 

 The species of this genus are numerous, and difficult to distinguish: the following classi- 

 fication of those known to me may enable them to be more easily recognised. 



A. Elytris interstitiis omnibus lrevigatis, impunctatis. 



Thorax subtus minus subtiliter punctatus E. politus Lee. Agass. Lac. Sup. 200. 



Thorax subtus subtilissime punctatus - E. laevigatus Lee. Ann. Lye. 5, 200. 



B. Thorax minus dense punctatus, elytris interstitiis internis Itevibus. 



Elytra interstitiis externis parce punctatis E. c i c a t r i c o s u s Lee. Ann. Lye. 4, 448. 



Elytra interstitiis exteruis et versus apicem "I _, _, . .,,._., „ _ 



i . , .. - K Clair villci Kirbti, i . Bor. Am. 62. 



dense punctulatis - - - J 



C. Thorax ct elytra confertissime punctata; his spatiis quadratis livigatis ornatis. 



Maior, thorace transverso, lateribua valde rotundatis E. intermedius Kirhy, ibid. 63. 



Thorax non transversus, angulis posticis prominulis. 



Thorax subtus, sternum, abdominisnue latera subti- ] „ ..„ . ,, t, „ , r -, n .r, 



,.. . , ' L > L. californicusi)/<?«. Bull. Mosc. 184o. 



liter punctulata ... J 



Thorax subtus, &c, distinctius punctata - E. punctatiss imus Lee. Lac. Sup. 210. 



Thorax subtus, &c, minus subtiliter punctata E. ruscar ius Say,Tr. Am. Ph. Soc. 4,417. 



Thorax non transversus, angulis posticis non prominulis. 



Thorax subtus, &c, distinctius punctata E. si mil is Lee. Ann. Lye. 4,440. 



E. sinuatus Lrc. (Agass. Lac. Sup. 210,) does not appear in the foregoing table; it is 

 closely allied to E. puuetatissimus, but differs in having a narrower thorax with less promi- 

 nent posterior angles; the elytra are narrower and more sinuate on the sides: as, how- 

 ever, there is not an exact agreement in these respects among all my specimens of E. 

 puuetatissimus, I am inclined to believe that for the present it is better to suppress the 

 species. 



E. ruscarius also shows a considerable variation in the form of the thorax, quite suffi- 

 cient to account for E. americanus Dej. (Sp. Gen. 5, 588.) The elytra of some of the 

 smaller specimens are comparatively much broader than in others, but after a very close 

 examination I can detect no specific difference. 



E. fuliginosus Say, (Trans. Am. Phil. Soc, 4, 417,) is probably my E. cicatricosus: only 

 the elytra are described, the rest of the specimen having been lost, so that the determi- 

 nation cannot be considered as certain. 



E. o b s c u r i o r Kirhij is unknown to me. 



z. Omophrones. 



The very different structure of the presternum requires this to be separated as a distinct 

 group, though Erichson and most other systematic authors have united il with the pre- 

 ceding: Kirby first proposed to form of it a separate family, which he called Omophronidse, 

 without giving any other character than the absence of a scutellum. 



It has been considered by Kirby, and by other writers, that this genus makes among 



