HOW INSECTS PROTECT THEMSELVES. 
521 
Collecting.—Pyralids abound everywhere, but it is not always one can 
get good unrubbed specimens. All that can be reared should be and the 
best specimens are thus obtained. Setting is troublesome and it is best 
to keep all in papers till time allows of a whole batch being done at once. 
Larvae may be blown or kept in formalin. They are found by patient 
seeking on plants, wherever rolled leaves are seen among decaying vege¬ 
tation and leaves at the roots of grasses in grass stems. A great fauna 
of Pyralids centres round grassy plants and few of such have been reared 
or studied. The wilder grasslands of India must abound in such forms 
and will prove a paradise to the collector of these moths. 
HOW INSECTS PROTECT THEMSELVES. 
A large part of the insect world is engaged in preying upon other 
insects, and while we do not know how far every insect has enemies 
directly attacking it in this manner, it is at least certain that a very 
large proportion are the food of either ordinary predators, stinging 
predators, insectivorous birds, lizards, frogs and the like or are the hosts 
of parasites. The insect organization reveals a variety of devices believed 
to be directed to securing a measure of immunity against these enemies, 
and it is possible to mention the more obvious ways in which 
immunity is aimed at; we cannot justly say that it is in all cases proved 
that these devices do secure immunity or do actually increase the 
measure of safety under which each insect lives : but the prevailing 
conclusions drawn from a mass of observations by the general body of 
observers is that these devices have little or no other meaning, and can 
be rationally explained in full only on the assumption that they are 
of value to the insect in this connection. Speaking broadly, the 
insect adopts one of four general methods : (1) to be distasteful; (2) to 
look distasteful; (3) to escape observation ; (4) to frighten enemies. 
Many insects are known to be distasteful to birds and insect-eating 
animals, on whom we can experiment; we associate this distastefulness 
with scents in many cases, scents produced by the excretion, at the 
will of the insect, of the aromatic oils. Most of our Pentatomidce 
are excellent examples; they have special orifices on the ventral 
surface whence issues a liquid which volatilises with the production 
of a usually very marked scent; it is only necessary to bring 
this scent within perceptive reach of birds and some animals to see 
unmistakable signs of aversion. The scents are often disagreeable to 
ourselves, but far less so than they are to animals. Such scents are found 
in Pentatomidce, Coreidce, Lygceidce, Pyrrhocoridce , some Reduviidce and 
