254 FOOD OF INSECTS. 



the rose.^ Most Ichneumons and Sphecina prey each upon a single species 

 of insect only, which therefore they would seem toTiave been formed for 

 the express purpose of keeping within due limits. Reaumur mentions 

 having once found in a parcel of decaying wood the nests of six different 

 kinds of the latter tribe, each of which was filled with flies of a distinct 

 species.^ Cerceris auritus and Philanthus Icetus in the larva state feed 

 solely on the weevil tribe of Coleoptera, the latter being restricted even to 

 the short-rostrumed family, as Otiorhynchus raucus, &;c.^; while Bembex 

 rostrata, another hymenopterous insect, selects flies, as Musca Casar, &tc.^ 



A very large proportion of species, however, are able to subsist on 

 several kinds of food. Amongst the carnivorous tribes, it is indifferent to 

 most of those which prey upon putrid substances from what source they 

 have been derived: and the predaceous insects, such as the LibeUulina, 

 Telcphorus, Empis, the Araneidce, &:c., will attack most smaller insects 

 inferior to them in strength, not excepting in many instances their own 

 species. The wax-moth larva (GaUeria Cereana) will for want of wax 

 eat paper, wafers, wool, &z;c.^: another Tinea described by Reaumur, 

 and before adverted to, attacks chocolate,^ which cannot have been its 

 natural food, even selecting that most highly perfumed ; and the Tinea 

 which devour dressed wool, but happily for the farmer and wool-stapler 

 refuse it when unwashed, must have existed when no manufactured wool 

 was accessible. The vegetable feeders are under greater restrictions, yet 

 probably the majority can subsist on different kinds of food. This is 

 certainly true of most lepidopterous larva;, several of which, as well as 

 many Coleoptera {Haltica oleracea, 6^c.), are polyphagous, eating almost 

 every plant. It is worthy of remark, however, that when some of these 

 have fed for a time on one plant they will die rather than eat another, 

 which would have been perfectly acceptable to them if accustomed to it 

 from the first.''' Here too it must be borne in mind, that by far the greater 

 part of insects feed upon 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 Lepidoptera, 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 remain- 

 ing orders. 



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

 the vegetable or animal kingdoms. But I oun;ht not to omit noticing that 

 some authors have conceived that several species feed upon mineral sub- 

 stances. ** Not to dwell upon Barchewitz's idle tale of East Indian ants 

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



> DeGeer, vi. 112. 



« Reaum. vi. 271.; and M. L. Dufoiir has recently described a species of sand-wasp 

 (Cerffm), which selects various species of .B?<;>res/« as the food of its progeny, some of 

 which are of the greatest rarity to collectors. 



' Enlnmolopache Bcmerkiingm (Braunschweig, 1799), p. fi. 



* Latreille, Ob.t. sur les Hijmenoptires. Ann. de Mux. xiv. 412. 



» Reaum. iii. 257. « Ibid. iii. 277. ' Ibid. ii. 324. 



8 For an instance in which an insect, usually subsisting upon animal food, derived nutri- 

 ment from a mineral substance, see Philos. Mag. &c. for January, 1821?. 



» Lesser, L. i. 259. 



