APPLIED ENTOMOLOGY 



CHAPTER I 

 INSECTS AND OTHER ANIMALS 



Among the larger groups of animals now recognized by science, the 

 one known as the Chorda fca is naturally the most familiar, including the 

 mammals, birds, reptiles, fishes, besides numerous forms less well known. 

 Another group, also familiar, and called the Mollusca, includes the snails, 

 clam etc., while a third, the Annulata, contains most of the more 

 commonly seen worms. The starfish and sea urchins, often seen at the 

 seashore, belong with other similar animals, to a fourth group called the 

 Echinodermata, and a multitude of tiny beings almost all too small to be 

 seen without the aid of a microscope, are included in the group Protozoa. 

 A sixth large group is composed mainly of soft, jelly-like animals, the 

 more common larger members being called jelly-fish, and to this the 

 name Ccelenterata is applied, and several other groups of less familiar 

 forms are also known. 



The largest group of all, however, is the Arthropoda, its members 

 found in the seas, in fresh water, on land, or even flying freely; a group 

 with remarkable differences of structure, and so abundant that all the 

 other animals taken together are less than one-sixth as many as the 

 Arthropods. Well-known members of this group are the lobsters, cray- 

 fish and crabs; scorpions, spiders, mites, ticks and " daddy long legs;" 

 the centipedes and millipedes; and last and most abundant of all, the 

 Insects. 



No one feature will serve to separate the Arthropods from all other 

 animals, but the possession by an animal of several of those here described 

 will enable the observer to determine in each case whether he is examin- 

 ing one of this group. In Arthropods the body is composed of a series of 

 more or less similar pieces or segments, placed one behind another, the 

 line of attachment of these to each other being usually somewhat evident 

 on parts of the body at least. This character is also shown, and indeed 

 more clearly, in some members of the Annulata, such as the common 

 earthworm. Another character of the Arthropods is the presence of 

 jointed legs (or appendages of some kind), as is indicated by the name 

 of the group, and these are not possessed by Annulates. The surface of 

 the body is covered by a secretion which hardens on exposure to the air, 



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