4: OUTLINES OF ENTOMOLOGY. 



horses, cows and sheep. This may seem strange to one who has given 

 the subject no attention, but a little careful observation will convince 

 him of its truth. 



It is impossible to obtain a definite idea of the structure of insects,^ 

 and their place in the scale of being, without comparing them critically 

 with other kinds of animals and noting the points in which they differ. 

 To obtain this knowledge without the aid of books would involve a 

 wide field of observation and a great deal of labor in systematizing 

 the information gained. Therefore, to aid and direct the observations 

 of the student, we will glance hastily over the outlines of the classifi- 

 cation of the animal kingdom as arranged by the great French natural- 

 ist, Cuvier, after whom it is called the "Cuvierian system." According 

 to this system all the animals, on or in the earth, monstrous or minute, 

 are arranged in the four following Sub-kingdoms : 



I. Backbone animals (Sub-kingdom VERTEBRA^'^uch as have an 

 internal bony frame termed a skeleton, the axis of which is a spinal 

 column composed of a number of peculiar joints called vertebrce. Ex- 

 amples — Man, Birds, Fishes and Eeptiles. 



II. Ringed or Articulate animals (Sub-kingdom A.RTicuLATA)y 

 having an external tough or horny framework composed of rings or 

 articulations enclosing the muscles and other soft tissues. Examples — 

 Insects, Spiders, Millepeds, Crabs. 



III. MoLLUSKS (Sub-kingdom Mollusca), soft-bodied animals 

 usually enclosed in shells. Examples — Snails, Slugs, Oysters. 



IV. Star or Radiate animals (Sub-kingdom Radiata). These 

 are formed somewhat upon the plan of a star or asterisk, with all the 

 members branching out from a common center. Examples — Star-fish^ 

 Sea Urchin, Coral animal. This division includes mostly marine ani- 

 mals. 



Each of these Sub-kingdoms is divided into several very distinct 

 classes. Passing over the classes of Backbone animals, we will con- 

 fine our attention to the Articulata, in which insects, although by no 

 means the largest representatives, occupy, on account of their more 

 specialized structure, the highest rank. The classes of Articulata 

 are ^ve in number, viz. : * Insects (^/wsec^rty), Thousand-legged worms 

 or Millepeds fMyriapodaJ, Spiders (Arachnida), Lobsters and Crabs 

 (Crustacea), and True Worms (Annelida), 



* According to Cnvier, whose plans wiU answer our present purpose. 



