232 MEANS OF DEFENCE OF INSECTS, 
was the multiplication of insects. Some species, the 
Aphides for instance, and the Grasshoppers and ies 
custs, have such an infinite host of enemies, that were it 
not for their numbers the race would soon be annihilated. 
—But as passive means of defence have detained us suf- 
ficiently long, it is enough to have touched upon this head. 
Let us then now proceed to such as may be called active ; 
in which the volition of the animal bears some part. 
Il. The active means of defence, which tend to secure 
insects from injury or attack, are much more numerous 
and diversified than the passive; and also more interest- 
ing, since they depend, more or less, upon the efforts 
and industry of these creatures themselves. When 
urged by danger, they endeavour to repel it either by 
having recourse to certain attitudes or motions; produ- 
cing particular noises; emitting disagreeable scents or 
fluids; employing their limbs; or weapons, and valour ; 
concealing themselves in various ways; or by counter- 
acting the designs and attack of their enemies by contri- 
vances that require ingenuity and skill. 
The attitudes which insects assume for this purpose 
are various. Some are purely imitative, as in many in- 
stances detailed above. I possess a diminutive rove- 
beetle (Aleochara complicans, K. Ms.) to which my at- 
tention was attracted as a very minute, shining, round, 
black pebble. This successful imitation was produced 
by folding its head under its breast, and turning up its 
abdomen over its elytra; so that the most piercing and 
discriminating eye would never have discovered it to be 
an insect.—-I have observed that a carrion beetle (Sepha 
thoracica, 1.) when alarmed has recourse to a similar 
