1852.] 39 



B. Thorax stria marginal! interiere nulla. 



t Mesosternum truncatum; prosternum bistriatum. 



Prosternum striis parallelis: (thorax stria exteriore nulla, corpus depresstim) 12. 

 Prosternum striis convergentibus : (thorax stria exteriore distinctavel nulla, 



corpus convexum) ......... 13. 



ft Mesosternum emarjiinatum : prosternum estriatum. {Platysoma hedich.) 



Prosternum postice planum, (corpus depressum) 14. 



Prosternum postice compressum et marginatum, (corpus cylindricum) . 15. 



The species found in the United States may be distributed as follows : 



1, corresponds to Omalodes Er. : the only United States is H. borealis (Omalo- 

 des borealis Lee.) 



2, contains only H. planipes (Omalodes Harrisii Lee.) The name Harrisii 

 being preoccupied for a species of group 6, must of course be changed. 



3, contains H. arcuatus Say; binotatus Lee; laevipes Er. and a new species 

 allied to arcuatus. 



*5, is composed of a Californian species, H. 6-striatus Lee. (An. Lye. ,1.) 



6, contains H. interruptus Beauv. {ohtusatus Harris) ; merdarius Payk ; im- 

 munisEr; Harrisii Kirby ; diversus Er. (stjjgicus hec.) ; fcedatns Lee. ; cogna- 

 tus Lee; marginicollis Lee, and one new species. 



7, contains H. dispar Lee; indistinctus Say; depurator Say; and one new 

 species. 



8, H. spretus Lee. ; curtatus Lee. ; and two new species. 



9, H. civilis Lee; ccenosus Er. {decisus Lee); punctifer Payk; abbreviatus 

 Fabr. ; bifidus Say, and perhaps H. repletus Lee. which I have not examined; it 

 is doubtful whether H, punctifer is really a native of our territory ; the only one 

 found may have been introduced. 



10, H. sedecimstriatus Say; americanus Payk. ; exaratus Lee. ; and two new 

 species. 



11, contains only H. bimaculatus Linn, {plliqmis Say). 



12, H. venustus Lee and corticalis Lee. Small flat species having the ap- 

 pearance of Platysoma ; the posterior tibiae are almost glabrous ; H. venustus 

 has the lobe of the prosternum shorter than any other species I have seen. 



13, H. subrotundus Er.and H.'vernus Say; small convex species, one of which 

 has an entire marginal stria on the thorax, the other none. A new species from 

 Mexico has an abbreviated stria at the margin of the thorax. 



14, contains the small flat species forming the genus Platysoma Leach as 

 amended by Erichson, the posterior tibiae are more or less distinctly toothed. 

 Our species are : H. carolinus Payk. ; depressus Payk. ; parallelus Say ; coarcta- 

 tus {Platy. coarctaticm Lee) ; and a new species. 



15, Cylindrical species allied to the preceding; H. cylindricus Payk. ; attenua- 

 tns (Plati/. atte?i7cat2imhec.) ', gracilis {Platys, gracile Lee, P. cylindrianiiX 

 Er., Hister frontalisW Say.) 



CiEROSTERNUS. 



Caput deflexum, mandibulis retractis sed non obtectis, acutis. 



Antennae sub frontis margine insertae, funiculo filiformi, capitulo triarticulato, 

 ovali, compresso, apice subtruncato. 



Prosternum latum quadratum, utrinque truncatum ; scrobiculi antennales angusti 

 profundi ad angulum thoracis inferne siti. Tibiae anticae compressae, subdila- 

 tatae, posteriores tenues glabrae ; tarsi posteriores non recepti. 



The body is globose, very convex ; the abdomen perpendicularly deflexed at 

 the tip : the funiculus of the antennae is filiform, the first joint longer and a little 

 thicker than the others ; the prosternum is very broad, truncate posteriorly, very 

 slightly rounded anteriorly; the cavities for the antennae are very deep^ situated 



* Group 4 is founded upon a curious nondescript Mexican species, H. rostatus, in 

 which the striae of the elytra are replaced by elevated ridges. 



