158 Mr. J. O. Westwood on the 
Antenne 10-articulate. 
Corpus supra planum; mentum profunde incisum ..Cryptogenius. 
Corpus plus minusve convexum ; mentum haud pro- 
fundé incisum. 
Caput sub pectus haud contractile; corpus haud 
globosum. 
Pedes mediocres, tarsis gracilibus. 
Prothorax maximus, anticé subbituberculatus. . Geobius. 
Prothorax mediocris, haud anticé subbituber- 
culatus. 
Prothorax anticé plus minusve retusus, dorso 
irregulari; caput seepius cornutum in ¢ ; 
maxillarum Jobus internus denticulatus. 
Mandibulis 4-dentatis ....-.eeeeeeee-- J riodontus. 
Mandibulis 3-dentatis ......-eeeeeeeesOrphnus. 
Mandibulis 2-dentatis ....0+.+e+.-0+ + Agidium. 
Prothorax et caput simplicia; maxillarum 
lobus internus in spinam curvatam dotadeus 
PToductus..cecccccccccevececoes 
Pedes abbreviati, tarsis crassis .....+.-+.e+-++1 rot, Phoberus. 
Caput sub pectus contractile; corpus globosum .. Acanthocerus; and 
the subgenera se- 
parated from it by 
Germar, in Zeit- 
schrift f. d. Ent. 
Fam. GEOTRUPIDE. 
Hysosorus, MacLeay. 
(Plate XI. fig. 1 and details.) 
This genus is at once distinguished by its sickle-shaped mandi- 
bles, a remarkable character, which neither MacLeay nor Guérin 
have represented in their figures illustrative of this genus. The 
labrum is entirely exposed and has its sides serrated, another 
peculiar character not noticed by MacLeay, whose description of 
the inner lobe of the maxillee ( lacinia interna subcrustacea intus 
ad apicem unidentata”) is also incorrect, as I have, on repeated dis- 
section, observed both lobes to be equally membranous and destitute 
of teeth. The labial palpi arise from large scapes, which MacLeay 
has mistaken for the anterior margin of the mentum; and instead 
of the ligula or labium being, as he says, “ vix distincta,” its two 
lobes are porrected beyond the basal joint of the palpi. Guérin 
also has neither represented the scapes to the labial palpi nor the 
lobes of the labium. The ungues are simpie in all the feet. 
The species are confined to the old world. 
Sp. 1. Hybosorus arator, Fabr., Mach. (oblongus, Dahl.) 
Habitat Europa Australi (Hispania, Gall. mer.) 
Long. corp. lin. 4. 
Note: H. arator, Lap. Hist. Nat. Ins, Col. vol. ii. p. 108, 
