INTRODUCTORY is 1 ;< :' <-.; 



THE PLACE OF BUTTERFLIES IN THE ANIMAL KINGDOM 



The Animal Kingdom is divided Into various subkingdoms. One of these is 

 the subkingdom of the Arthropoda. This word is derived from the Greek nouns 

 apBpov (arthron) meaning joint, and wovs (pous) meaning foot. The Arthropoda 

 are animals the bodies of which are made up of a series of rings or segments jointed 

 together, and the other organs of which are likewise composed of tubular bodies 

 similarly united. All arthropods are invertebrates; that is to say, they do not have 

 backbones and internal skeletons, such as are possessed by fishes, reptiles, birds, 

 and mammals, including man. Vertebrate animals have endoskeletons, "inside 

 skeletons." In a ham, for instance, the bone is internal to the muscular parts, 

 or meat, and lies near the middle. The muscles of a man clothe his bones. In the 

 arthropods, on the contrary, the hard parts clothe the muscles. Arthropods are 

 therefore said to have exoskeletons, "outside skeletons." The body, the legs, and 

 other organs of an insect or a crab consist of a series of hollow tubes held together 

 \y flexible skin at the points of union, and controlled in their movements by muscles 

 pull from the inside. The meat of a lobster is inside of the shell, or exo- 



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