34 
ELEMENTS OF ENTOMOLOGY. 
leapers are remarkably large and thick, with the shank long and com- 
monly arched,, by which means they possess great strength and power 
for leaping: the legs are broad, serrated, and sharp at the edges, iu 
those accustomed to dig in the earth ; and such as are of the aquatic 
kind have the legs, especially the posterior pair, long, Hat, and ciliated, 
or fringed at the edge with hair. The leapers are well exemplified in 
the saltatorial kinds of Curadio and Chrysomela; and the swimmers, in 
the genera Hydrophilus and Dytkus. 
The Coxa, a small joint at the base, connects the thigh to the body, 
and moves in a. corresponding cavity of the collar or thorax in the lirst 
pair, or breast in the two posterior ones. This part varies in form : in 
the Ccramhices, CoccindUt, 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 die 
earth, have the coxa broad and Hat; diis is also observable in some of 
the aquatic beetles : in the J)ytici die coxa of the posterior legs is 
imbedded in the trunk, and in the Hlatta, lepisma, and others which 
walk very rapidly, it is compressed into a lamellate form. 
Femur, the T/iig/i. There is more diversity in the form of the thigh 
titan 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 ot repose it. is parallel to the inferior surface of die body. It is 
limited to a 1'orward and backward motion with respect to die 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 die C'«- 
mbus, 4'C. the thigh has two little prominences at the base called tro- 
chanters, which appear to be intended for removing the muscles from 
the axis of the articulation. Those which require strong muscles 
adapted for leaping, have die diigh not only thick but generally elon- 
gated; as in the Grylliis and Locusla tribes, the Puliccs or fleas, &c. 
And in the Aphodius, Gcotrupes, Sfc. ( Scarabtei Linn.),, and also the 
mole cricket, (all which burrow in the earth,) the thigh is moved widi 
much force, and has an articulated surface corresponding to the flat 
part ot the coxa on which it rests. This part is sometimes spinous. 
Tima, 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 habits of the insect re- 
quire it to be applied : in the natatorial kinds it is usually flat and cili- 
ated — at least the tibia of the posterior pair; and in many others, as in a 
variety of the burrowing kinds of beedes, it is serrated. The shank is 
more frequently serrated or spinous than the thighs. 
The Tarsus, 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, Hymcnoptera, and Diptera. In 
some oi these, however, and also in the Hemiptera, there are only four 
