So 
INSECTS. 
of the grains of mould, to which consistency is given by means of a gummy secre¬ 
tion furnished by the larva. Many form with this secretion a hard case, the outer 
side covered with chips of the surrounding bark, which, owing to their similarity to 
the surroundings, serve as a protection from observation. Others spin a silken egg- 
shaped cocoon, sometimes flocculent and broken, sometimes formed of yards and 
yards of silken thread, emitted from the mouth and passed over and under, across 
more interesting of these 
and round, until the cell is complete. Amongst the 
cocoons is that of the emperor-moth, which forms a short tubular exit closed 
against the entrance of earwigs and other insects by a circular series of line bristles 
directed outwards and converging to a point. The principle of contrivance is the 
same as that employed in the manufacture of lobster-pots; but here the process is 
reversed, for in this case it admits of a ready egress but prevents any entrance. 
Moths whose pupa stage is passed within an external cocoon have a double task 
before them when the time is ripe for an emergence. The pupa itself—as does also 
the chrysalis of butterflies—splits at the dorsal suture above the thorax, and the 
moth emerges, ferreting a way through one end of the cocoon, which seems to be 
softened by moisture from within, and thus escapes. The imago, or perfect insect, 
having now emerged, climbs to some point of vantage, where the wings, still very 
small, though completely formed, are allowed to hang downwards, expand and 
harden in the air. After a few hours they are stiff* and ready for use. 
At no stage in their lives are lepidopterous insects free from the 
En6mi6s ^ ^ 
attacks of enemies. In the egg-state they fall a prey to beetles and 
small birds, and as larvae they are extremely liable to receive a deadly thrust with 
the ovipositor (or sting) of an ichneumon. As the ichneumon-grubs grow at the 
expense of their host, scarcely a tissue in the whole body may remain, save those 
needful for the carrying out of life-supporting functions. And at last, when the 
grubs are themselves ready to pupate, and have no further need of their host, they 
finish up the rest and the larva dies—chiefly because there is nothing left to live. 
The enemies of the imago, whether butterflies or moths, are numerous. Birds, 
bats, dragon-flies, etc., pursue and harass them whenever they happen to meet with 
them. The marvel is that any remain alive to lay eggs and perpetuate the species. 
In the struggle to escape detection and capture, all unconscious 
Mimicry. 
though it may be, arises the phenomenon alluded to above, and known 
as protective mimicry. The kindred phenomenon of protective colouring, when the 
moth or butterfly merely resembles in hue the bark, leaf, or twig on which it 
rests; also protective resemblance, simply when insects take the form of objects, 
such as twigs, dead leaves, bits of decayed wood, flakes of white bird-droppings; these 
are all well known. But protective mimicry means more, it implies the actual 
mimicking either the form, colour, or habits of some other insect which is either 
too savage or unpleasant to make it a desirable object of food; as, for instance, 
the clear-wing moths mimic gnats, bees, wasps, ichneumons, etc. Perhaps the 
most curious instance is that of the Kallimas or dead-leaf butterflies of Northern 
India, whose upper sides are richly coloured, while the under sides are dull brown 
mottled and veined with darker colours. So conspicuous a butterfly would not 
fail to fall a ready prey to foes. If it but settle for an instant, however, the 
sharpest eye will not detect them. The secret lies in the colour and veining of the 
