MEANS OF DEFENCE OF INSECTS. 219 
instruments with which Providence has furnished it for 
this purpose. 
I. The principal pass?ve means of defence with which 
Insects are provided, are derived from their colour and 
form, by which they either deceive, dazzle, alarm, or an- 
noy their enemies; or from their substance, involuntary 
secretions, vitality, and numbers. 
They often decezve them by imitating various substances. 
Sometimes they so exactly resemble the soil which they 
inhabit, that it must be a practised eye which can di- 
stinguish them from it. Thus, one of our scarcest British 
weevils (Curculio nebulosus, L.), by its grey colour spotted 
with black, so closely imitates the soil consisting of white 
sand mixed with black earth, on which I have always 
found it, that its chance of escape, even though it be hunt- 
ed for by the lyncean eye of an entomologist, is not small. 
Another insect of the same tribe (Brachyrhinus scabricu- 
lus, F.), of which I have observed several species of com- 
mon dors (Harpalus, Latr.) make great havoc, abounds in 
pits of a loamy soil of the same colour precisely with itself; a 
circumstance that doubtless occasions many to escape from 
their pitiless foes.—Several other weevils, for instance 
Brachyrhinus niveus and cretaceus, F., resemble chalk, and 
perhaps inhabit a chalky or white soil. 
Many insects also are like pebbles and stones, both 
rough and polished, and of various colours ; but since this 
resemblance sometimes results from their attitudes, I 
shall enlarge upon it under my second head: whether, 
however, it be merely passive, or combined with action, 
we may safely regard it as given to enable them to elude 
the vigilance of their cnemies. 
