CHAPTER III. 

 CLASSIFICATION OF INSECTS. 



Having examined the locust with the aid of the fore- 

 going description, the student should make his studies 

 comparative by carefully examining a cricket and a green 

 grasshopper. Then he might turn to the following de- 

 scriptions of examples or types of the order of white 

 ants, dragon-flies, hugs, beetles, flies, moths, bees, etc., and 

 as the result of his work he will be able to grasp the fact 

 that the species of insects, as a rule, have bodies composed 

 of seventeen segments, which are arranged in three regions, 

 viz., a head, thorax, and hind body or abdomen ; that the 

 thorax bears ttvo pairs of wings, and three pairs of jointed 

 or segmented legs; that they breathe by internal air-tubes 

 opening externally by spiracles, and that in growing they 

 either develop directly, or undergo a complete metamorphosis. 



The class of insects is divided or classified into orders, 

 families, genera, and species, and the study of the classi- 

 fication of insects is called Systematic Entomology. 

 The class, as regards existing forms, is divided into sixteen 

 orders, as follows, beginning with the lowest or wingless 

 order, Thysanura, and ending with the highest or most 

 complicated group, the Hymenoptera. 



CLASS INSECTA. 



Jointed animals with a distinct head, thorax, and abdomen; three pairs 

 of legs, and usually two pairs of wings; breathing by trachea; usually 

 with a metamorphosis, viz., a /area/, pupal, and adult stage. 



Sekies I. Ametabola, or with an incomplete metamorphosis. 



Order 1. Thysanura. — Wingless, minute, with a spring, or ab- 

 domen ending in a pair of caudal stylets; usually no compound 

 eyes; no metamorphosis. (Examples: Podura, Campodea, Scolopen- 

 drella, Lepisma.) 



Order 2. Dermaptera. — Body flat; the abdomen ending in a for- 

 ceps; fore wings small, elytra-like; hind wings ample, folded under 

 the first pair. (Forficula.) 



