418 INSECT A. 



or six strong teeth. The mentum is proportionally shorter and 

 wider than that of the same Coleoptera, and less narrowed superi- 

 orly. The mesosternum is frequently prolonged into a horn or blunt 

 point, extending between the second legs and even beyond them. 

 The scutellum is usually large. The tarsial hooks are generally 

 unequal. With the exception of a small number, these Xylophili 

 are peculiar to the equatorial countries of the western continent. 



Here, as in all the preceding Scarabasides, we find no axillary 

 piece(l) filling the interval comprised between the posterior angles 

 of the thorax and the exterior angles of the base of the elytra. 



We will first speak of those subgenera in which the middle of the 

 pectus presents no point or horn. 



Hexodon, Oliv. Fab. 



The body is almost orbicular and plane beneath; the head square 

 and received into a deep emargination of the thorax; the outer mar- 

 gin of the elytra dilated and preceded by a small groove; the legs 

 are slender, and the hooks of the tarsi very small and equal. 



The labrum is not apparent. The antennal club is small. The 

 maxillae are strongly dentated(2). 



Cyclocephala, Lai. — Chnlepiis, Mac L. — Melolontha,, Fab. 



The body ovoid; head free; elytra slightly bordered, without any 

 lateral dilatation or groove; terminal joint of the anterior tarsi cla- 

 vate, with unequal hooks, both bifid. 



The anterior margin of the labrum is apparent. The mandibles 

 are narrow, without any notable emargination or sinus on the outer 

 side, and project but slightly outwards(3). 



In the following subgenera, the sternum projects between the 

 second pair of legs in a conical point, more or less long, pointed or 

 rounded at the extremity. 



(1) A lateral portion of the sternum larger and thicker than usual, and which 

 perhaps corresponds to that small rounded scale (the tegula of some authors) 

 found at the origin of the superior wings of Hymenoptera. See the M^m. sur le 

 thorax des Insectes, by M. Audouin. 



(2) See Ohv., and Lat, Gener. Crust, II, p. 106. 



(3) The Melolonthae ^emiwa^a, barbata, castanea, signata, ferruginea, melanoce- 

 pkala, pallens, &c-, of Fabricius. In the first, the mandibles are strong, arcuated, 

 and hooked at the end. Those of the M. signata, melanocephala, &c. , are smaller, 

 straight, truncated, or obtuse at the end. The summit of the maxillae and mentum 

 is also furnished with hairs. From such characters we might form a separate sub- 

 genus of these and analogous species. They all bplnng to South America. 



