MOTIONS OF INSECTS. 303 



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

 rina) ; spiders (Araneidce] ; long-legged spiders (Pha- 

 langidte] ; and scorpions (Scorpionidce) : Polypods^ or 

 those that havefourteen legs, consisting of the woodlouse 

 tribe (Oniscidae)\ and Myriapods, or those that have 

 more than fourteen legs often more than a hundred 

 composed of the two tribes of centipedes (Scolopendridte) 

 and millepedes (Julidce). The first of these classes may 

 be denominated 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 a . 



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 b ; 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 



a The most common number of joints in the tarsus is from two to 

 five ; but the Phalangidae 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 Colcoptera 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 universally. For not to 

 mention the instance of Pselaphus, clearly belonging to the Bra- 

 chyptera 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. b Hi. 284. 



