UTILITY OF INSECTS. 19 



in the iiistninKMitality of a liirjj^e ]>roportioii of insects in their character 

 of scavengers, wliereby the doconiposition of decayed and ortensive 

 matters, t)oth animal and vegetable, is etiected and accelerated ; and 

 thiidly, in the agency of insects in causing the fertilization of i)lants, 

 especially those witli very deep corrollas, and those wliich have the bar- 

 ren and jHoductive tiowors upon different plants, by carrying upon their 

 legs, in tlu'ir search for honey, the fertilizing pollen from one liower to 

 anotlier. A long cha])ter might bo written ui>on each of these topics, 

 but we have space here barely to enumerate them. 



DIVISION OF INSECTS ACCORDING TO THE NATURE OF THEIR FOOD. 



From this point of view all insects may be divided into two classes — 

 the carnivorous insects, or those which eat animal food, [Hniropluuja) ; 

 and the herbivorous insects, or those which subsist upon vegetable sid»- 

 stances, [Vhytophafia). Each of these classes is again divisible according 

 ly as the insects which compose it take tln'ir food in a fresh and living 

 state, or in a state of deiiay. The former are called [)redaceous insects 

 {Aflcphof/n), when they live upon animal prey; and the latter are desig- 

 nated by the name of scavengers [Rypophaija). Those iuse(;ts which eat 

 living animal food, are still further divisible into predaceous insects 

 ])roper, which seize and devour their prey, and parasite insects, which 

 live witliin the bodies of their victims and feed ui)on their substance. 



Those insects which feed upon decaying animal matter present three 

 divisions : tirst, general scavengers, whi(;h devour particles of putrescent 

 matter wherever they may l)e found; second, those which live ex(;lu- 

 si\ely in or upon the bodies of dead animals, {N'ecropha(fa) ; and thirdly, 

 those which are found exclusively in animal excrement, {Coprophafja). 



The herl)ivorous insects may be divided in a similar manner into those 

 which eat fresh v^egetable food, {Thalcrophmja)^ and those which subsist 

 upon vegetable matters in a state of decay, {tSaproplKUja). They can 

 also be usefully classified according to the particular parts of the plant 

 which they devour, into lignivorous or wood-eating insects, (Xylophaga); 

 the folivorous, or leaf-eating insects, {FhyUophiuja)] and the fructivor- 

 ous, or fi-uit-eating insects, {Carpopha(in). 



The abov«' Greek terms in parenthesis have been used chietly in con- 

 nection with the insects of the Coleopterous order, in which these <li\'er- 

 sities of food-habits exist to a much greater extent than in any of tlie 

 other orders, but the terms themselves are of general signihcalion, and 

 being ver^' concise and comprehensive, they might, not imi)roperly, l>e 

 used in speaking of insects iu all the orders, so far as they are appli- 

 cable. 



