220 FOOD OF INSECTS. 



which eat iron 1 , or on the stone-eating caterpillars recorded in the Memoirs 

 of the French Academy 2 , 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 

 Ephemera 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 3 , 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 the Ephemerae. 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 Lepidoptero, 

 which are there chiefly taken in court-yards, near the margins of drains, 

 &c. 4 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 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 larvae 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 Jjictionnaire Physique. 



4 Mr. Doubleday bas observed tbe 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 a 

 few yards of mud (Westwood, Arc. Ent. i. p. 144.) The same habit may occa- 

 sionally be noticed in this country. 



