LETTER XXII. 
MOTIONS OF INSECTS. (Larva and Pupa.) 
AMONGST the means of defence to which insects have 
recourse, I have noticed their motions. These shall be 
the subject of the present letter. I shall not, however, 
confine myself to those by which they seek to escape 
from their enemies; but take a larger and more com- 
prehensive survey of them, including not only every spe- 
cies of locomotion, but also the movements they give to 
different parts of their body when in a state of repose: 
and in order to render this survey more complete, I shall 
add to it some account of the various organs and instru- 
ments by which they move. 
Whenever you go abroad in summer, wherever you 
turn your eyes and attention, you will see insects in mo- 
tion, ‘They are flying or sailing everywhere in the air; 
dancing in the sun or in the shade; creeping slowly, or 
marching soberly, or running swiftly, or jumping upon 
the ground ; traversing your path in all directions; cours- 
ing over the surface of the waters, or swimming at every 
depth beneath; emerging from a subterranean habita- 
tion, or going into one; climbing up the trees, or de- 
