4 OUR INSECT FRIENDS AND FOES 



by a number of common features. That is to 

 say, we find that they all have a more or less 

 tough skin or integument ; they have the body 

 more or less clearly divided into segments ; and 

 their system of appendages legs, jaws, feelers, 

 and the like no matter what part of the body 

 they are attached to, agree in being covered 

 with a hard or tough integument similar to that 

 of the body, and in being divided by a number of 

 joints into segments. Now, these features, 

 common to the five creatures which we have 

 just examined, are characteristic of a very 

 extensive group of animals comprising the 

 Phylum or sub-Kingdom Arthropoda. Of the 

 five members of this important sub-Kingdom, 

 which we have taken as our examples, four are 

 air-breathers, and one, the Lobster, is an aquatic 

 animal differing from the other four not only in 

 its mode of life, but in having the respiratory 

 organs, in the form of gills or branchiae, modified 

 to suit its particular mode of life. The Lobster 

 is a representative of the class Crustacea of the 

 sub-Kingdom Arthropoda; the centipede of the 

 class Myriapoda ; the Scorpion, and its cousin 

 the Spider, are representatives of the class 

 Arachnida ; and the Beetle and Butterfly of the 

 class Insecta. 



The two classes of this great sub-Kingdom 

 of the Arthropoda with which we are now 

 most immediately concerned, are the class 

 Insecta, comprising the Cockroaches, Grass- 

 hoppers, Ants, Bees, Wasps, Aphides, Lady- 

 birds, Dragon-flies, Mosquitoes, Houseflies, 

 Beetles, and Butterflies ; and the class Arachnida, 



