1402 THE STORY OF THE UNIVERSE 



the pupa, and the imago, or perfect insect." In fact, 

 however, the various groups of insects differ widely 

 from one another in the metamorphoses they pass 

 through: in some, as in the grasshoppers and crickets, 

 the changes consist principally in a gradual increase 

 of size, and in the acquisition of wings ; while others, 

 as, for instance, the common fly, acquire their full 

 bulk in a form very different from that which they 

 ultimately assume, and pass through a- period of in- 

 action in which not only is the whole form of the 

 body altered, not only are legs and wings acquired, 

 but even the internal organs themselves are almost 

 entirely disintegrated and re-formed. 



The following list gives the orders or principal 

 groups into which the Class Insecta may be divided. 

 I will not, indeed, here enter upon my own views, but 

 will adopt the system given by Mr. Westwood in his 

 excellent Introduction to the Modern Classification 

 of Insects. He divides insects into thirteen groups, 

 and with reference to eight of them it may be said 

 that there is little difference of opinion among en- 

 tomologists. These orders are by far the most nu- 

 merous, and I have placed them in capital letters. 

 As regards the other five there is still much differ- 

 ence of opinion. It must also be observed that Prof. 

 Westwood omits the parasitic Anoplura, as well as 

 the Thysanura and Collembola. 



ORDERS OF INSECTS ACCORDING TO WESTWOOD 



1. HYMENOPTERA . Bees, Wasps, Ants, etc. 



2. Strepsiptera . . Stylops, Zenos, etc. 



3. COLEOPTERA . . Beetles. 



4. Euplexoptera . . Earwigs. 



