142 INSECTS OR HEXAPODA. 



food being taken. The pupal skin shows the general outline 

 of the insect — legs, antennae, wings, &o., being clearly defined 

 (fig. 65, b). Chrysalis is the term generally used in Butterflies, 

 which are pale-coloured and more or less angular (c). In Flies, 

 and some Hymenoptera, the pupa is found in the old larval skin, 

 which hardens and forms a brown case, called the puparium 

 — the " flax-seed " stage of the Hessian Fly (a, i). In some 

 diptera the pupte are spiny (fig. 66). During this pupal period 

 the majority of the larval organs are broken 

 down into a soft granular mass, which he- 

 comes remodelled into the adult. This pro- 

 cess is called histolysis. The pupal stage, 

 again, is very variable in length, but not to 

 such an extent as in the larva. There are 

 often two or more broods, or generations, of 

 insects during the year ; in some the summer 

 pupal state only lasts a week or so, whilst 

 the winter pupal state lasts some months. 

 Fiii 66 -^ pdpa of insects pass the winter in all four stages, 

 fsr"hti ">^'i"*od*i ™*'''y ^^ °'^^ (Vapourer Moth), others as 

 pupse (Hawk Moths), whilst some hibernate 

 in the larval (Currant Moth) and adult (Tortoise-shell Butter- 

 fly and Queen Wasps) conditions. 



Injuries are caused by insects both to plants and animals. 

 The damage is done in a variety of ways, such as by eating the 

 leafage, by tunnelling into the stems and leafage, boring into 

 fruit and seeds, and boring into the stems, even into the hardest 

 wood. Both growing and stored grain and seed are attacked, 

 also provisions, household goods, and furniture. Animals are 

 attacked by insects sucking their blood, and others have para- 

 sitic habits, as exemplified by the Gad-flies and A^'arble-flies 

 respectively. 



The senses of insects are of much interest to us, and well 

 worthy of our study. Sir John Lubbock's work on the ' Senses 

 of Insects,' which treats this subject most fully, shows that 

 it is one of some importance economically, as ^vell as of deep 



