FOOD OF INSECTS. 389 



under greater restrictions, yet probably the majority can 

 subsist on different kinds of food. This is certainly true 

 of most lepidopterous larvae, several of which as well as 

 many Coleoptera (Haltica oleracea, &c.) are polyphagous, 

 eating almost every plant. It is worthy of remark, how- 

 ever, 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 a . 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 Lepidopte- 

 ra, 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 hymenopte- 

 rous 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 con- 

 ceived that several species feed upon mineral substances. 

 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 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 Ephemera; to be earth, that being the 

 only substance ever found in their stomachs and in- 

 a Reaum. ii. 324. b Lesser, L. i. 259. c x. 458, 



