34 



ELEM£M3 OK ENTOMOLOGY. 



leapcrs are remarkably large and thick, with the shank long and com- 

 monly arched, by which means they possess great strengtli and power 

 for leaping: the legs are broad, serrated, and sharp at the edges, in 

 those accustomed to dig in the earth; and such as are of the aquatic 

 kind have the legs, especially the posterior pair, long, flat, and ciliated, 

 or fringed at the edge with hair. The leapers are well exemplified in 

 the saltatorial kinds of Curcidlo and Chrysomelu ; and the swimmei-s, in 

 the genera Hydrophilns and Di/licus. 



The Coxa, a small joint at the base, connects the thigh to the body, 

 and moves in a corresponding cavitj' of the collar or thorax in the lirst 

 pair, or breast in the two posterior ones. This part varies in form : in 

 the Ccramhices, Coccinellcc, and other insects in which the feet serve for 

 walking only, its shape is globular: such as require that the feet should 

 have a lateral motion, and which is necessary to those that dig into the 

 earth, have the coxa broad and flat; this is also observable in some of 

 the aquatic beetles : in the Dt/ticl the coxa of the posterior legs is 

 imbedded in the trunk, and in the B/atta, lepismn, and others which 

 walk very rapidly, it is compressed into a lamellate form. 

 . Femur, the I'/iigfi. There is more diversity in the form of the thigh 

 than the coxa to which it is united. The articulation of these two parts 

 is internal, and is produced in such a manner that when the animal is 

 in a state of repose it is parallel to the inferior surface of the body. It is 

 limited to a forward and backward motion with respect to the first piece. 

 The nature and extent of the motions of the thigh appear to determine 

 its form. In those insects which walk much and fly little, as in the Ca- 

 rabus, ^c. the thigh lias two little prominences at the base called ti-o- 

 c/ianlers, wliich appear to be intended tor remo^'ing the muscles from 

 the axis of the articulation. Those which require stroug muscles 

 adapted for leaping, have the thigh not only thick but generally elon- 

 gated ; as in the Gryllus and Locuata tribes, the Pidiccs or fleas, &c. 

 And in the Aphodiux, Geotrupes, Sfc. {Scarabu-i Linn.), and also the 

 mole cricket, (ail which burrow in the earth,) the thigh is moved with 

 much force, and has an articulated surface correspontling to the flat 

 part of the coxa on which it rests. This part is sometimes spinous. 



TiBi.\, or Shank, is the third joint of the legs, and moves in an an- 

 gle according to the direction of the thighs. The figure of this part 

 depends essentially on the uses to which the habij:s of the insect re- 

 quire it to be applied : in the natatorial kinds it is usually flat and cili- 

 ated — at least tlie tibia of the posterior pair; and in many others, as in a 

 variety of the burrowing kinds of beetLes, it is serrated. The shaiik is 

 more frequently serrated or spinous than the thighs. 



The Tarsi;s, or Foot, is the fourth joint or last portion of the leg 

 except the claw. This part consists in general of five joints : this is 

 usually the number in the Coleoptera, Ilymcnoptcra, and Dipfera. In 

 some of these, however, and also in the Haniptera, there are only four 



