238 COLEOl'TERA OF NORTH AMERICA. 



II. Abdominal spiracles in part situated on the superior portions of the 

 ventral segments, the last one usually visible behind the elytra ; the 

 rows of spiracles feebly diverging. Ligula sometimes free, usually 

 connate with tlie mentum. Melolonthim:. 



III. Abdominal spiracles (except the anterior ones) situated in the dorsal 

 portion of the ventral segments, forming rows which diverge 

 strongly ; last spiracle usually visible behind the elytra. Ligula 

 always connate with the mentum (larvre with tlie lobes of the 

 maxillae connate). Pleurosticti. 



Sub-Family I.— SCARABJ^IDAE LAPAROSTICTI. 



Besides the characters given by the position of the abdominal 

 spiracles in the membrane connecting the ventral and dorsal seg- 

 ments, and the ligula separate from the mentum, these insects, or 

 at least a portion of them, exhibit characters not found in the 

 other families. 



In many of them the upper surface of the head is much dilated 

 on the front and sides (but never reflexed, as in most Melolon- 

 thidae); the clypeal suture is distinct, and ascends towards the 

 vertex, forming an angle; the mandibles are usually thin ]ilates, 

 frequently membranous, small, and invisible, except on dissection; 

 sometimes, however (Geotrupes, etc.), they are well developed. 

 In some of the genera the antennte are 11-jointed. The club of 

 th.e antenna consists of but three joints, except in Pleocoma, and 

 in some the first joint of the club is hollowed out so as to receive 

 the second or even the last joint. 'Ihe tarsi are armed with simple 

 claws in all of our genera, except Phanajus, where the claws are 

 wanting; in some genera of Coprini the anterior tarsi are want- 

 ing. The usual bisetose onychium is wanting in Acanthocerini, 

 Trogini, Aphodiini, and some Coprini. 



The arrangement of this sub-family is adopted nearly as in 

 Lacordaire's work, with the exception of the removal of the tribe 

 Glaphyrini to the next sub-family, and the establishment of two 

 new tribes. 



The species all Hve on decomposing matter, most of them in 

 excrements, and a few in fungi. 



The tribes are as follows : — 



Abdomen with six visible ventral segments ; 



Antenna 9- or 10-jointed (club always 3-jointed) ; 



Posterior tibise with a single spur. CorniNi. 



Posterior tibia? with two spurs ; 



