mTRODUCTIOK 7 



Bombycid moths, so well represented by the common silkworm. Many 

 caterpillars bury themselves in the ground before becoming pupse ; 

 others lie on the surface, only drawing together a leaf or two by silken 

 attachments ; some introduce particles of sand, earth, or wood into 

 their cocoons, many hairy larvee even interweaving their own hairs ; 

 and in others, again, a higher degree of protection is obtained by the 

 abundance in the material of a hard-setting gummy secretion. In 

 those cases where the pupa is wholly exposed (as in nearly all butter- 

 flies), or is in the incomplete open-meshed sort of cocoon, there is no 

 difficulty in observing the changes in the form of the caterpillar prior 

 to its last moult, which consist mainly in its contracting to much 

 shorter, but at the same time thicker, dimensions, in the acumination 

 of the abdominal region, and in the shrinkage and withdrawal from 

 external projection of the head and legs. The abdominal pro-legs 

 now finally disappear, and it is only in the last cast-off skin of the larva 

 that any record of their having existed remains. 



The caterpillars of Lepidoptera exhibit considerable variety in general 

 form, those of several groups not presenting the ordinary sub-cylin- 

 drical elongated shape so familiar to all in the silkworm, but being 

 more or less widened, shortened, and depressed. Some have the skin 

 smooth, while in others it is more or less roughened or granulated; 

 and in a great number of others it is set with hairs, bristles, or spines. 

 Among the hairy kinds there is immense diversity in the distribution 

 and arrangement of the hairs, which are sometimes generally dispersed, 

 but as often disposed in tufts, or springing from tubercles, or arranged 

 in bands or local stripes and patches. Some of the more rigid and 

 acute spines in the larvee of certain Bombycid moths are modified into 

 weapons both defensive and ofiensive, being not only exceedingly sharp 

 and serrated, so as to pierce and greatly irritate, but grouped in clus- 

 ters or fascicles exsertible at the will of the animal. No other insect 

 larvge approach caterpillars in beauty and variegation of colour and 

 marking, whether we look to the smooth or hairy kinds. The few 

 almost colourless or very dull-coloured caterpillars are those that live 

 in the stems or at the roots of plants. The prevalent colour is green, 

 and this is highly protective in concealing from their enemies creatures 

 feeding almost entirely on leaves. But some of the most brilliantly 

 variegated patterns of caterpillars are really protective in nature, as is 

 well seen among the very large and beautiful larvae of the Hawkmoths 

 {SpMiujidcB), where the stripes and spots of strongly-contrasted colours 

 are adapted to the lights and shades, the outlines and tints, of the 

 leaves, twigs, and buds of the plants the larv^ frequent. Where this 

 adaptation to surroundings does not prevail, it has been found in many 

 cases that the gaudy, conspicuous caterpillars are unpalatable to birds 

 and other insectivorous animals, and so are not liable to the persecution 

 so generally experienced by their tribe. Some caterpillars of moths 

 {Psychidce, and many of the Tmem) construct from the first a descrip- 



