498 ACTS OF LEAPING :—FLEA; ORIOKET. 
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 Rabbit, when 
Fig. 237.—HArE ASCENDING A Hixt, 
moving slowly, advances the fore-feet two or three stepsi 
alternately, the posterior limbs remaining inactive ; and the 
body having been lengthened by these means, the posteriox 
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 simila 
manner, 
' 662. It is among Insects that we find the most extraordi 
nary Hee of leaping, considered with reference to the siz 
: of the animals tha 
possess them. Thu 
the Flea will sprin, 
to a height equal 
200 times the leng 
of its body. Let 
imagine a Kanga 
or a Tiger doing 
same! In many 
the leaping insects 
the hind legs are of great length, as in the Grasshoppef 
and Cricket tribe (fig. 238); and in one curious family 
that of the Podwras or spring-tails, the leap is accomplishe; 
by the sudden extension of the tail, which is ordinarily ber 
under the body (fig. 239), A very remarkable kind of leap 
Fig. 238,—Cricket, 
