MOTIONS OF INSECTS. 303 



that have eight legs, including the tribes of mites {Aca- 

 rina) ; spiders [Ay-aneidcc) ; long-legged spiders {PJia- 

 langidce) ; and scorpions {Scoryionidce) : — Poli/pods, or 

 those that havejbioieen legs, consisting of the woodlouse 

 tribe {Oiiiscidce) ; — and Mi/riaj)ods, or those that have 

 more than fourteen legs — often more than a hundred — 

 composed of the two tribes of centipedes {ScolopeJidrida) 

 and millepedes {Jididce). The first of these classes may 

 be denominated prope?; and the rest wiproper 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 *. 



In voalking and nmnmg, 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 contrary 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 number of joints in the tarsus is from two to 

 five ; but the Phahxngidae have sometimes more than forty. In these, 

 under a lens, this part looks like a jointed antenna. 



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

 primary divisions of the Coleojilera order from the number of joints 

 in the tarsus j but this, although perhaps in the majority of cases it 

 may afford a natural division, will not universally. For — not to 

 mention the instance of Pselapliw;, clearly belonging to the Bra- 

 chyptcra — both Oxytelus, Grav., and another genus that I have sepa- 

 rated from it {Carpalimus, K. Ms.), have only two joints in their 

 tarsi. In this tribe, therefore, it can only be used for secondary di- 

 visions. — K. •' iii. 284. 



