ANNULOSA: INSECTA. 215 



usually provided with locomotive feet, which 'do not corre- 

 spond with those of the adult, though these latter are usually 

 present as well. In some cases the larva is destitute of legs, 

 or is ' apodal.' The larva is also provided with masticatory 

 organs, and usually eats voraciously. In this stage of the meta- 

 morphosis the larvsB constitute what are usually called ' cater- 

 pillars ' and 'grubs.' Having remained in this condition for 

 a longer or shorter length of time, and having undergone re- 

 peated changes of skin, or 'moults,' necessitated by its rapid 

 growth, the larva passes into the second stage, and becomes a 

 'pupa.' The insect is now perfectly quiescent, unless touched 

 or otherwise irritated, is incapable of changing its place, and 

 is often attached to some foreign object. This constitutes what 

 in the case of the Lepidoptenra is generally known as the 

 * chrysalis,' or ' aurelia.' The body of the pupa is usually co- 

 vered by a chitinous pellicle, which closely invests the animal. 

 In some cases the pupa is further protected within the dried 

 skin of the larva ; and in other cases the larva immediately 

 before entering upon the pupa- stage spins, by means of spe- 

 cial organs for the purpose, a protective case, which surrounds 

 the chrysalis, and is termed the ' cocoon ' (fig. 68). 



Having remained for a variable time in the quiescent pupa- 

 stage, and having undergone the necessary development, the 

 insect now frees itself from the envelope which obscured it, 

 and appears as the perfect adult, or 'imago,' characterised by 

 the possession of wings. 



SEXES OF INSECTS. The great majority of Insects, as is the 

 case with most of the higher animals, consist of male and fe- 

 male individuals ; but there occur some striking exceptions to 

 this rule, as seen in the Social Insects. In those organised 

 communities which are formed by Bees, Ants, and Termites, 

 by far the greater number of the individuals which compose 

 the colony are either undeveloped females, or are of no fully 

 developed sex. This is the case with the workers amongst 

 Bees, and the workers and soldiers amongst Ants and Termites. 

 And these sterile individuals, or 'neuters,' as they are com- 

 monly called, are not necessarily all alike in structure and 

 external appearance. Amongst the Bees all the neuters re- 

 semble one another, but amongst Ants and Termites they are 

 often divided into ' castes,' which have different functions to 

 perform in the general polity, and differ from one another 

 greatly in their characters. 



In all the above-mentioned insects, the males are relieved 

 from the performance of any of the duties of life, except that 

 of propagating the species ; and the females which are gene- 



