LEGS. 287 



are provided with internal muscles and nerves. The 

 joints have received a series of names analogous to 

 those of the legs of the higher animals. They are the coxa, 

 trochanter, femur, tibia, and tarsus. The coxa (136, a) is the 

 basal joint articulating with the sternum, and very variable 

 in form. The trochanter (136, li) is a very small piece con- 

 necting the preceding Avith the thigh or femur (136, c), 

 which in general is the thickest part of the leg, and in leap- 

 ing insects greatly thickened, and sometimes toothed beneath. 

 The next piece is the shank or tibia (136, d), a piece general- 

 ly somewhat shorter and more slender than the femur, and 

 often gradually thickened towards the tip, where it is armed 

 with one or two spm-s or spines {calcarea, 136, 138, dd), 

 varying in their number and size in adjacent groups. The 

 terminal part of the leg is termed the tarsus (136, e), divided 

 into several joints, never exceeding five, which is the number 

 always found in the majority of insects with membranous 

 wings, undefended by wing-cases. In many beetles the 

 number is variable, from two to five, and the same is the 

 case in the Neuroptera, &c. The under surface of these 

 tarsal joints is generally clothed with short hair or down, 

 often forming a kind of cushion or brush ; sometimes, also, 

 the under-side exhibits several smaU circular membranous 

 plates or soles (fig. 139, fore tarsus of a male Dyticus). 

 The penultimate joint is also often divided into two lobes, 

 and the terminal joint is also generally terminated by two 

 small bent hooks {ungues, 136, f), between which, in many 

 insects, there are one, two, or three small, often membra- 

 naceous, appendages, termed pulvilli (fig. 141, 142, 143, 

 z,z,z). In some coleopterous insects the penultimate joint 

 is very minute (fig. 140). Messrs. Kirby and Spence re- 

 gard the fore-legs of insects as arms rather than legs, and 

 accordingly term the anterior tarsus the hand, calhng the 

 basal joint the planta or palm. That the fore-legs are high- 



