CHECKS TO NATURAL INCREASE. 1 93 



animals allowed to arrive at maturity, their numbers 

 would quickly be such as to make the earth uninhabitable ; 

 as there would soon be neither food nor room for 

 themselves, much less for other animals. The increase is 

 checked however in many ways. Extremes of temperature 

 and climate, dearth of food, disease, fungi, and bacteria 

 destroy countless numbers of them every season. They 

 serve largely as food for other animals which could not 

 themselves live if deprived of the abundant supply 

 furnished by the surplus progeny of the insecta. 



Many insects feed upon others, the larv;e of one living 

 in and upon another, as in the case of the Ichneiniwnidce; 

 the perfect forms consume the larvae and pups of 

 other species and often feed upon the imagines of other 

 kinds.* 



Birds subsist largely upon insects in all stages of their 

 metamorphosis, many living almost entirely upon them and 

 destroying incredible numbers. Frogs, toads and lizards, 

 feed upon them, as do also the monkeys and many other 

 tropical vertebrates. The soft and juicy larvaj are particu- 

 larly attractive morsels to the Insectivora, the fat grub and 

 unctuous caterpillar being eagerly sought for in every crack 

 and crevice in field, hedge and wood. 



That insects constitute a staple part of the food of 

 other animals is very well known to every naturalist. 

 Many experiments have been made with the object of 

 testing the selective faculty and appetency of animals in this 

 respect ; especially by Professors E. B. Poulton, Lloyd- 



*The word 'imago' as representing ihe final stag'e in insect metamorphosis is 

 objectionable and its plural 'imagines' is particularly so. It was used by Linnjeus, as 

 he says, "because, having laid aside its mask and cast off its swaddling bands, (the insect) 

 ■' being no longer disguised or confined, or in any respect imperfect, is now become a true 

 " representative or image of its species and is qualified to fulfil the laws of nature in 

 "propagating its kind " — Mr. J. T. Lingard suggests instead 'matura' (matiiro '=■ to 

 ripen) " as it would indicate at once the state reached, whilst its termination, both singular 

 "and plural, would accord with both larva and pupa. " I quite agree with this happy 

 suggestion and shall be glad to sec itadopied to represent the perfect msect. INI.L.S. 



