2.') 



3. Tho eye. This in insects is an exquisite object for 

 study. Why nature has been so profuse in her bounty as to 

 give from 4 to 20,000 eyes to an insect we cannot in the least 

 understand, nor why the caterpillar should only have twelve, 

 and the moth 14 or 15,000; but such is the case, and al- 

 though we cannot comprehend why the Great Designer in 

 his wisdom has so arranged it, yet we are able to appre- 

 ciate the structural mechanism and marvel at its beautiful 

 design. The diagram before you is a beautiful section of 

 a compound eye , copied from a drawing made by Strauss 

 Durchheim. 



You perceive from the brain the optic nerve is thrown 

 oflF («) ; from its periphery or convex surface a set of short 

 nerves arise ; they form a membrane, the general retina 

 of the eye (c) ; before this membrane there is another called 

 the chorroid (<f), with its pigraentum or colouring matter. 

 This differs in colour ; in the cockchafer it is of a bril- 

 liant red, in others green or intense black. From the ex- 

 pansion of the retina (c) the true optic nerves arise («) ; 

 they proceed forwards and then enter the ocelli or little 

 eyes. In each eye we find a hexagonal chrystallised sub- 

 stance like the vitreous humour of our own eye ; upon this 

 we have a double convex lens, then a little black line which 

 may be said to resemble the iris, and finally the cornea or 

 external transparent coat of the eye. The eye of insects 

 is immoveable, but with this combination of power, and 

 the eyes being seated on the lateral side of the head, they 

 have the facility of viewing objects in almost every di- 

 rection, and which no doubt must materially assist its 

 flight. 



4. The ailk gland ; having no longer the necessity for 

 exuding that material, becomes altered in its function, and 

 now supplies the mouth with saliva, becoming a salivary 

 gland. 



5. The legs, as you sec by this diagram, are very different 

 to what they were in the larval state : they are now only 

 six in number, arc distinctly jointed, each joint being bold 

 and perceptible, and each separate part having a distinct 



