INTRODUCTION. 5 



Lepidopterous Larvae, in common with those of most 

 other Orders of Insects, are subject to the attacks of para- 

 sites, the principal of which are certain Hymenoptera, 

 known as Ichne.umonida', or Ichneumon Flies. The eggs 

 of these little destroyers are introduced into the body of 

 the caterpillar, by the long and sharp ovipositor of the 

 parent fly, which displays the greatest energy and perse- 

 verance in searching after the particular kind of Larva upon 

 which her young are destined to feed. The grubs of the 

 ichneumon, as soon as hatched, immediately commence de- 

 vouring the body of the caterpillar, but, led by a wondrous 

 instinct, avoid doing injury to the important vital organs ; 

 so that the Lepidopterous larva generally continues to live 

 till it has attained its full size, and often assumes the Chry- 

 salis state before the ichneumons cause its death. The latter 

 sometimes eat their way through the sides of the Larva, 

 forming their little cocoons around it, and sometimes undergo 

 their metamorphosis within its body, only emerging when in 

 their perfect state. A large number of species of these para- 

 sites ai'e known to science ; indeed, it is probable that every 

 Caterpillar has its own peculiar kind of Ichneumon Fly. 

 The importance of the services of these Hymenoptera, in 

 keeping within due bounds the numbers of Lepidopterous 

 Insects, and consequently of their plant-destroying Larvae, 

 is incalculable, and for exceeds the aggregate services of 

 birds, bats, spiders, wasps, predaceous beetles, and other foes. 

 Several species of Diptera, or Two-winged Flies, also find 

 their sustenance as larvae in the bodies of living Caterpillars ; 

 and, in some instances, the single parasite, when fully grown, 

 is almost as large as the Larva it has devoured. 



The PuptE, or Chrysalides, of Lepidoptera present a 

 very different appearance from that of the Larvas. Instead 

 of an active, incessantly-devouring insect, provided with 

 numerous and efficient instruments for eating and progression, 

 we behold a motionless, helpless, mummy-like animal, in- 

 capable of taking nourishment, or of self-defence. The 

 position of the limbs of the Lepidopteron about to be de- 

 veloped is generally distinctly visible. They are so aiTanged 

 as to occupy the smallest possible space ; the antenna?, haus- 

 tellum, and legs being closely appressed to the breast ; and 

 the v/ings as closely fitting to the sides, one above the other, 

 the tips of the front margins just meeting below the breast. 

 The eyes are usually very apparent ; and the spiracles are 

 present, though often differing in number and position from 

 those of the larvae. When first disclosed, the Chrysalis is 

 soft and moist, and frequently of a different colour to that 



