220 FOOD OF INSECTS. 
which eat iron’, or on the stone-eating caterpillars recorded in the Memoirs 
of the French Academy*, which are now known to erode the walls on 
which they are found solely for the purpose of forming their cocoons, 
Reaumur and Swammerdam have both stated the food of the larvae of 
Ephemere to be earth, that being the only substance ever found in the 
stomachs and intestines, which are filled with it. This supposition, which 
if correct renders invalid the definition by which Mirbel (and my friend 
Dr. Alderson of Hull long before him) proposed to distinguish the animal 
and vegetable kingdoms, is certainly not inadmissible ; for, though we might 
not be inclined to give much weight to Father Paulian’s history of a flint- 
eater who digested flints and stone, the testimony of Humboldt seems to 
prove that the human race is capable of drawing nutriment from earth, 
which, if the odious Ottomaques can digest and assimilate, may doubtless 
atford support to the larvz of the Ephemera. Yet, after all; it is perhaps 
more probable that these insects feed on the decaying vegetable matter 
intermixed with the earth in which they reside, from which after being 
swallowed it is extracted by the action of the stomach : like the sand that, 
from being found in a similar situation, Borelli erroneously supposed to be 
the food of many Testacea, though in fact a mere extraneous substance. 
The majority of insects, either imbibing their food in a liquid state, or 
feeding on succulent substances, require no aqueous fluid for diluting it. 
Water, however, is essential to bees, ants, and some other tribes, which 
drink it with avidity; as well as in warm climates to many Lepidoptera, 
which are there chiefly taken in court-yards, near the margins of drains, 
&c.4 Even some larve which feed upon juicy leaves have been observed 
to swallow drops of dew: and one of them (Odonestis potatoria), which 
(according to Goedart) after drinking lifts up its head like a hen, has re- 
ceived his name from this circumstance. That it is not the mere want of 
succulency in the food which induces the necessity of drink is plain from 
those larvz which live entirely on substances so dry that it is almost un- 
accountable whence the juices of their body are derived. The grub of an 
Anobium will feed for months upon a chair that has been baking before the 
fire for half a century, and from which even the chemist’s retort could 
scarcely extract a drop of moisture; and will yet have its body as well 
filled with fluids as that of a leaf-fed caterpillar. 
By far the greater part of insects always feed themselves. The young, 
however, of those which live in societies, as the hive and humble-bees, 
wasps, ants, &c., are fed by the older inhabitants of the community, which 
also frequently feed each other. Many of these last insects are distin- 
guished from the majority of their race, which live from day to day and 
take no thought for the morrow, by the circumstance of storing up food. 
Of those which feed themselves, the larger proportion have imposed upon 
‘them the task of providing for their own wants ; but the tribe of Spheges, 
wild bees, and some others, are furnished in the larva state by the parent 
insect with a supply of food sufficient for their consumption until they 
have attained maturity. 
1 Lesser, L. i, 259. 2 x, 458, 3 Dictionnaire Physique. 
4 Mr. Doubleday has observed the habit which butterflies have of settling on 
damp mud on road sides in the United States, where they congregate in groups, 
sometimes literally consisting of hundreds of individuals clustered together on @ 
few yards of mud (Westwood, Are. nt. i. p. 144.) ‘The same habit may occa- 
sionally be noticed in this country, 
