MEANS OF DEFENCE OF INSECTS. 261 
cover itself in about two hours. There are often many 
layers of these grains upon the back of the insect, so as 
to form a coat of greater diameter than its body. When 
it becomes too heavy and stiff, it is thrown off, and a new 
one begun?.—The larvee of the various species of the 
tortoise-beetles (Cassida, L.) have all of them, as far as 
they are known, similar habits, and are furnished besides 
with a singular apparatus, by means of which they can 
elevate or drop their stercorarious parasol so as most 
effectually to shelter or shade them. The instrument by 
which they effect this is an anal fork, upon which they 
deposit their excrement, and which is sometimes turned up 
and lies flat upon ther backs ; at others forms different anr 
gles, from very acute to very obtuse, with their body; and 
occasionally is unbent and in the same direction with it>, 
In some species the excrement is not so disgusting as you 
may suppose, being formed into fine branching filaments. 
This is the case with C, maculata, L.‘.—In the cognate 
genus Imatidzwm, the larve also are merdigerous ; and 
that of J. Leayanum, Latr., taken by Colonel Hardwicke 
in the East Indies, also produces an assemblage of very 
long filameuts, that resemble a dried fucus or a filamen- 
tous lichen.—The clothing of the Zine, clothes-moths 
and others, and also of the case-worms, having enlarged 
upon in a former letter’, I need not describe here. 
Some insects, that they may not be discovered and be- 
come the prey of their enemies when they are reposing, 
conceal themselves in flowers. The male of a little bee 
2 Reaum. iii. 220— Compare Vallisnieri Esperienz. ed Osservax. 
195. Ed. 1726. > Reaum. 233— 
© Kirby in Linn. Trans. iii. 10. 4 Von, I. 4th Ed. 460-70. 
