MOTIONS OF INSECTS. 307 



tribes of mites (Acaridce) ; spiders (A)'ancidce) ; long- 

 legged spiders (Phalangidce) ; and scorpions {Scorpi- 

 onidce). — Poij/pods, or those that hB.ve fourteen legs, 

 consisting of the woodlouse tribe {Oniscidce); — and 

 Myriapods, or those that have more than fourteen legs 

 — often more than a hundred — composed of the two 

 tribes of centipedes (Scolopendridce) and millepedes 

 (Julidce). The first of these classes may be denomi- 

 nated proper, and the rest improper insects. The legs 

 of alL seem to consist of the same general parts ; the 

 hip, trochanter, thigh, shank, and foot ; the four first 

 being usually without joints (though in the Araneidce, 

 &c. the shank has two), and the foot having from one 

 to above forty S 



In walking and running, the hexapods, like the larvae 

 that have perfect legs, move the anterior and posterior 

 leg of one side and the intermediate of the other alter- 

 nately, as I have often witnessed. De Geer, however, 

 affirms, that they advance each pair of legs at the same 

 time**; but this is contrai*y to fact, and indeed would 

 make their ordinary motions, instead of walking and 

 running, a kind of canter and gallop. Whether those 



" The most common tiumber of joints in the tarsus is from tv/o to five ; 

 but the Phaiangidse have sometimes more than forty. In tiiese, under a 

 lens, this part looks like a jointed antenna. 



Geoffroy, and after him most modern entomologists, has taken the 

 primary divisions of the Coleoptera order from the number of joints in the 

 tarsus; but this, although perhaps in the majority of cases it may afford 

 a natural division, will not iiniversally. For — not to mention the in- 

 stance of Vselaphus, clearly belonging to the Slapkt/linidtE — both O.rytC' 

 lus, Grav., and another genus that I have separated from it {Carpali- 

 mus, K. Ms.), have only two joints in their tarsi. In this tribe, therefore, 

 it can only be used for sccojidary divisions, K. " lii. ^8i. 



X 2 



