INTRODUCTION. 



"In the other orders {Diptera [two-winged flies], 

 Hymenoptera [bees, wasps, ants], Neuroptera [caddis-fly], 

 Lepidoptera [butterflies and moths], Coleoptera [beetles]) 

 the larva, on its last change of skin, assumes a new form 

 known as the chrysalis or pupa, in which stage it lies 

 dormant and nearly motionless, shut iip like a body in the 

 shroud, until the last change takes place, when it comes 

 out as the perfect insect. This chrysalis in some cases 

 merely consists of the hardened skin of the animal itself, 

 and is left unprotected and bare in the open air, or in the 

 earth or other place of concealment ; but in other cases 

 a cocoon or case is made by the larva for it, previous to 

 and in anticipation of the change, in some spun like the 

 cocoon of the silk-worm, in others composed of fragments 

 of earth or bits of wood, etc., glued together " (Murray). 



Insects in their perfect state, are distinguished from 

 other articulate animals by the possession of six legs 

 and two antennae (" feelers "), and by the division of the 

 body into three distinct regions — the head, thorax, and 

 abdomen, of which the second bears the organs of motion. 

 The mouth of the insects exhibits remarkable modifica- 

 tions. In some it is used exclusively for biting, in others 

 for suction, whilst in others again it is constructed for the 

 performance of both these actions. The eyes of insects 

 are compound and sessile; sometimes simple eyes are 

 added to them. 



Insects are all unisexual 'animals. Hermaphroditism, 

 where it occurs, is quite exceptional in its nature, and 

 very rarely gives rise to fertile individuals. The females 

 are usually larger and broader than the males, but in 

 most cases the structure of the apex of the abdomen at 

 once indicates the sex ; besides the antennse and tarsi 

 (feet) often present well-marked differences in the two 



