FOOD OF INSECTS. 389 



different substances in their different states of existence, 

 eating one kind of food in the larva and another in the 

 imago state. This is the case with the whole Order Le- 

 pidoptera, which in the former eat plants chiefly, in the 

 latter nothing but honey or the sweet juices of fruit, 

 which they have often been observed to imbibe ; and the 

 same rule obtains also in regard to most dipterous and 

 hymenopterous insects. Those which eat one kind of 

 food in both states, are chiefly of the remaining orders. 



I have said that insects, like other animals, draw their 

 subsistence from the vegetable or animal kingdoms. But 

 I ought not to omit noticing that some authors have 

 conceived that several species feed upon mineral sub- 

 stances a . Not to dwell upon Barchewitz's idle tale of 

 East Indian ants which eat iron b , or on the stone-eating 

 caterpillars recorded in the Memoirs of the French Aca- 

 demy C 5 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 their stomachs and in- 

 testines, 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 king- 

 doms, 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 d , 

 the testimony of Humboldt seems to prove that the hu- 

 ma nrace is capable of drawing nutriment from earth, 



a For an instance in which an insect, usually subsisting upon 

 animal food, derived nutriment from a mineral substance, see Philos. 

 Magaz. &c. for January 1 823. 2. 



b Lesser, L. i. 259. x, 458. t! Dictionnaire Physique. 



