498 
ACTS OF LEAPING :—FLEA : CRICKET. 
of their bodies places them in continual danger of oversetting • 
they therefore take a zig-zag course. In ascending a hill, 
however, their progression is greatly favoured by the length 
of their posterior extremities (fig. 237). The Eabbit, when 
moving slowly, advances the fore-feet two or three steps 
alternately, the posterior limbs remaining inactive; and the 
body having been lengthened by these means, the posterior 
legs are suddenly extended together, and then drawn for¬ 
wards : thus the rabbit walks with the fore and leaps with 
the hind pair of legs. The Frog moves in a very similar 
manner. 
662. It is among Insects that we find the most extraordi¬ 
nary powers of leaping, considered with reference to the size 
of the animals that 
possess them. Thus 
the Flea will spring 
to a height equal to 
200 times the length 
of its body. Let us 
imagine a Kangaroo 
or a Tiger doing the 
same ! In many of 
the leaping insects, 
the hind legs are of great length, as in the Grasshopper 
and Cricket tribe (fig. 238); and in one curious family, 
that of the Poduras or spring-tails, the leap is accomplished 
by the sudden extension of the tail, which is ordinarily bent 
under the body (fig. 239). A very remarkable kind of leap is 
