COLEOPTERA. 409 



This subgenus conducts us naturally to the first of the following 

 section, that of the Arenicoli. These Scarabseides, with the Apho- 

 dii and Psammodii, are the only ones whose elytra entirely cover the 

 posterior extremity of the abdomen, so that the abdomen is com- 

 pletely concealed; but they are distinguished from the latter by seve- 

 ral characters. The labrum is coriaceous, and most frequently juts 

 out beyond the epistoma. The mandibles are corneous, and usually 

 salient and arcuated. The terminal lobe of the maxillae is straight, 

 and has no inward curve. The third and last joint of the labial palpi 

 is always very distinct, and at least almost as long as the preceding 

 one. With some few exceptions their antennae are composed of ten 

 or eleven joints. 



These Insects are also coprophagous, make deep holes in the 

 ground, fly particularly during the evening, after sun-set, and coun- 

 terfeit death when seized. According to M. Leon Dufour, the ali- 

 mentary canal of Geotrupes, one of the principal subgenera of this 

 section, is somewhat shorter than in Copris, and the stomach pre- 

 sents no vestige of papillae( l). 



Here Geotrupides, Mac Leay the labium is terminated by two 

 lobes, or salient ligulae, the mandibles are generally salient and arcu- 

 ated; the labrum is either wholly or partially exposed, and the an- 

 tennae in most of them are composed of eleven joints. The body is 

 black or reddish, and the elytra smooth or simply striated. The 

 males generally have horns, or differ in other external characters 

 from the females. They feed more particularly on excrementitious 

 matters. 



The antennae of some are composed of nine joints. 



^Egialia, Lat. Jlphodius, Fab. 



The labrum short, transversal, scarcely apparent and entire; ter- 

 minal point of the mandibles bifid; internal lobe of the maxillae cor- 

 neous and bidentated; the body short and inflated; thorax transversal; 

 abdomen gibbous; the four posterior tibiae thick and incised, the two 

 last terminated by two compressed and almost elliptical or spatuli- 

 form spurs; the two anterior tibiae have no tooth on the inner side; 

 the posterior thighs are the largest(2). 



Chiron, Mac Leay. Biosomus, Dalm. Si?iodendron, Fab. 

 The Chirones, in their antennal club, which is rather semi-pecti- 



(1) See Ann. des Sc. Nat., Ill, p. 234. 



(2) Psammodius arenarius, Gyll., Insec. Suec. I, p. 6; Scarabsp-us ghbosus, Panz , 

 Faun. Insect. Germ., XXXVII, 2; Aphodius arenarius. Fab. 



Vol. Ill 3 B 



