272 MOTIONS OF INSECTS. 
or hang upon smooth surfaces; the great strength and 
spring in the legs of such as leap; the strong-made feet 
and talons of such as dig; and, to name no more, the 
admirable faculty of such as cannot fly, to convey them- 
selves with speed and safety, by the help of their webs, or 
some other artifice, to make their bodies lighter than the 
ain.) 
Since the motions, and instruments of motion, of in- 
sects are usually very different in their preparatory states, 
from what they are in the imago or perfect state, I shall 
therefore consider them separately, and divide my subject 
into—motions of larvee,—motions of pupge,—and motions 
of perfect insects. 
I. Amongst Jarve there are two classes of movers— 
Apodous larve, or those that move without legs,—and 
Pedate larvee, or those that move by means of legs. I 
must here observe, that by the term legs, which I use 
strictly, I mean only jointed organs, that have free mo- 
tion, and can walk or step alternately ; not those spurious 
legs without joints, that have no free motion, and cannot 
walk or take alternate steps; such as support the middle 
and anus of the larvee of most Lepidoptera and saw-flies 
( Tenthredinide). 
Apodous larvee seldom have occasion to take long jour- 
neys; and many cf them, except when about to assume 
the pupa, only want to change their place or posture, 
and to follow their food in the substance, whether animal 
or vegetable, to which, when included in the egg, the 
parent insect committed them. Legs therefore would be 
* Physico-Theol. Ed, 13, 363. 
