240 PASSALID^. 



with numerous lateral teeth, and its articulation with the 

 femur strengthened at the base l)y a locking tooth. The tarsi 

 are short, with simple symmetrical claws and short pulvillus. 

 The middle and hind tibiae are often fringed with stiff hairs 

 externally. 



The prosternum is narrow and produced, in front, where it 

 forms a chin-plate beneath the head, and behind, where it is 

 generally visible as a free lobe. The front coxae are never 

 widely separated, and in the Aulacocyclin^ are brought so 

 close together as to be almost m contact, the prosternum being 

 reduced to a knife edge between them. The middle coxae also 

 are only narrowly separated b}^ the meso- and metastenium, 

 which are produced to sharp points at their junction, and 

 owing to the unusual length of the mesosternum and the loose 

 articulation of the middle femora with the coxae, the former 

 are capable of bemg brought forward so as to lie side by side 

 along the middle line of the body. The hind coxae are long and 

 narrow and exactly transverse, comjDletely separatmg the 

 metasternum and abdomen. The legs are subject to remark- 

 ably little variation. They are short and not very stout, the 

 front tibiae furnished along the whole length of the outer edge 

 with sharp scraper-teeth, and bearing near the base of the 

 inner edge a strong tooth which hts into a deep pit m the 

 femur, firmly locking them together. As usual, the front tibia 

 bears a single articulated spur near the base of the tarsus, and 

 the four posterior tibiae have each two terminal spurs. The 

 middle and hind tibia? usually terminate in two shaq) processes 

 and are frhiged with hairs, both internally and externally, the 

 fringes of the middle tibia bemg sometimes very thick and long. 

 The five-jointed tarsi are always short and quite simple and 

 end in a pair of simple and symmetrical claws, with only a 

 mmute pulvillus between them. 



The antennae are short and stout, attached immediately in 

 front of the eye and composed of 10 joints. The scape is not 

 long and the following joints are attached at its extremity, so 

 that the articulation does not form an elbow. The nine joints 

 following the scape form three rather well-marked groups of 

 three joints each, the first three small and of simple bead-like 

 shape, the next three larger, but much narrower on the inner 

 than on the outer side of the antenna, rendering possible the 

 rolling up of its terminal part which is so characteristic of the 

 family. The last three joints form the club in most Passalid^e, 

 but in some genera the narrow ends of the three preceding 

 joints are produced into supjilementary leaflets, which are 

 always of unequal length and shorter than the last three, with 

 which they do not usually form a uniform series. At an 

 earlier stage, therefore, there were probably only three club- 

 joints, although it remains possible that six existed in a still 



