48 INSECTA. 



transverse square. The inferior side of the thighs is trenchant with 

 a sulcus; the two anterior are furnished with a tooth, and the four 

 posterior tibiae are narrow, arcuated, and somewhat dentated; tlie 

 tarsi are glabrous*. 



The other Insects of this tribe, with similar legs in both sexes, 

 differ from the preceding in their mentum, Avhich occupies trans- 

 versely the greater portion of the xinder part of the head, and has 

 the form of a heart truncated inferiorly or at base. The thorax is 

 always transversal, emarginate or concave before and arcuated late- 

 rally, either trapezoidal and widest posteriorly, or strongly dilated 

 laterally and narrowed towards the posterior angles. The labrum is 

 emarginated. 



Most of these Insects are cinereous, and live on the ground in sandy 

 localities. 



Sometimes the thorax is widened before, or near the middle of its 

 sides, and narrowed posteriorly. The base of the jaws is exposed. 

 In 



Heteroscelis, Lat., 



We observe two stout teeth on the outer side of the four first tibiae, 

 one in the middle, and the other terminal. The posterior extremity 

 of the prtesternum is prolonged, laminifonu, flattened, and received 

 into an emargination of tlie mesosternum. The body is oval, and 

 rounded at both ends; the lateral edges of the thorax are strongly 

 arcuated, and simply narrowed near the posterior angles. The an- 

 tennse are slightly and gradually enlarged towards the extremity f. 



Machla, Herbst. 



The antennae, terminated by a little globuliform club composed ot 

 the three last joints ; they can be received into cavities underneath 

 the sides of the thorax, which are extremely thick and rounded %• 

 In 



ScoTiNus, Kirb., 



The antennae are also terminated by a little club, but in wiiich the 

 two last joints are almost confounded ; they are not susceptible of 

 being received into particular cavities. The thorax is dilated be- 

 fore §. 



Sometimes the thorax is almost trapezoidal, gradually arcuated 

 throughout the whole extent of its lateral edges, and is not abruptly 

 narrowed posteriorly. The mentum covers the base of the maxilise. 



The two last joints of the antennae are united in a small club. 

 Such are the 



* Blaps tibialis, Fab. 



f Pimeliadentipes, Fab.; Platyiwtus reticulatus, ejusd. ; — Pimelia obscura, Oliv. ; 

 Insects from the Cape of Good Hope. 



t Platynotus serraius, Fab. 



§ Scoti7ius crenicolb's, Kirb., Lin. Trans, XII, xxi, 14, a subgenus peculiar to 

 South America. 



