CHAPTER II. 



INSECTS AND THEIR NEAR RELATIVES. 



Branch Arthropoda (Ar-throp'o-da). 

 The Arthropods {Ar' thro-pods). 



If an insect, a spider, a- scorpion, a centipede, or a lobster 

 be examined, the body will be found to be composed of a 

 series of more or less similar rings or seg- 

 ments joined together; and some of these 

 segments will be found to bear jointed 

 legs (Fig. i). All the animals possessing 

 these characteristics are classed together 

 as the Branch Arthropoda, 



A similar segmented form of the body 

 is found among worms ; but these are dis- 

 tinguished from the Arthropods by the 

 absence of legs. It should be remembered 

 that many animals commonly called worms, 

 as the tomato-worm, apple-worm, etc., are, 

 not true worms, but are the larvae of in- 

 sects (Fig. 2). The angle-worm is the 

 most familiar example of a true worm. 



The Branch Arthropoda is the largest 

 of the branches of the Animal Kingdom, 

 including many more known species than all the other 

 branches taken together. Our common representatives are 

 distributed among four classes: these are the Crustacea, 

 the Arachnida, the Myriapoda, and 'the Hexapoda. The 



9 



Fig. I.— An insect show- 

 ing segmented form of 

 body. 



