670 EXTERNAL ANATOMY OF INSERTS. 



in Gonyleptes K. the posterior ones are armed internally 

 with very strong ones; with which, as the legs converge 

 at their knee a , they may probably detain their prey. The 

 knee-pan {Gonytheca) of the thigh, or the cavity at its 

 end, which receives the head of the tibia, is very conspi- 

 cuous in the weevils ; but in no insects more than in 

 Locusta \ in which tribe it deserves your particular at- 

 tention. 



d. Tibia or Cubitus c . The tibia or shank is the fourth 

 joint of the leg, which according to the hypothesis lately 

 alluded to is the analogue, in the anterior leg of the car- 

 pus or carpal bones, and in the Jour posterior ones of the 

 tarsus or tarsal bones of vertebrate animals. This may 

 be called the most conspicuous of the articulations of the 

 leg; for though it is generally more slender and often 

 shorter than the thigh, it falls more under the eye of the 

 observer, that joint being more or less concealed by the 

 body: it consists in general of a single joint; but in 

 the Araneidce and Phalangidce it has an accessory one, 

 often incrassated at its base, which I have named the 

 ~Epicnemis d . 



With respect to the articulation of the tibia with the 

 thigh — we may observe that in general it is by means of 

 three processes or condyles, two lateral and one interme- 

 diate, of the head of the former joint e : the lateral ones 

 are usually received by a cavity or sinus of the gonytheca 



;i Linn. Trans, xii. t. xxii./. 16. b Plate XIV. Fig. 5, 



and XXVII. Fig. 15. r"\ - Plates XIV. XV. XXVII. s". 



6 Plate XXVII. Fig. 21. s"'. M. Savigny (Anim. sans Vertebr. 1. 

 i. 46. Note b.) seems to think that this structure obtains in all his 

 Apiropods; viz. the Octopod Aptera, Arachnida, and Myriapoda: but 

 it seems to me evident only in the two tribes mentioned in the text. 



e Plate XXVII. Fig. 6, 16, 17. i>". 



