FOOD OF INSECTS. 255 



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 larva3 of 

 Ephemera to he earth, that being the only substance ever found in the 

 stomachs and intestines, which are filled w'ith 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 afford support to the larvae of Ephemeras. 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 sup- 

 posed 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.^ Even some larvae 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 

 received its 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 larvae which live entirely on substances so dry that it is almost 

 unaccountable 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 

 distinguished 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. 



' X. 458. * Didionnaire Physique. 



3 Mr. Doubleday has observed the habit which butterflies have of settling on damp mud 

 on road sides in the United States, where the}' congregate in groups, sometimes literally 

 consisting of hundreds of individuals clustered together on a few yards of mud (West- 

 wood, Arc. Ent. i. p. 144.) The same habit may occasionally be noticed in this country. 



