OUR INSECT FRIENDS 

 AND ENEMIES 



CHAPTER I 



THEIR RELATION TO THE ANIMAL KINGDOM 



IF we examine any insect, large or small, in any 

 save the egg stage, we note at once that it has its skeleton 

 on the outside of the body. Not much of a skeleton in 

 some cases, e.g., a caterpillar, a slug or a maggot; a 

 very resistant and rigid shell or body wall in others, as 

 in some beetles which may be run over by a heavy 

 wagon wheel without being any the worse, or may pass 

 unchanged through the digestive system of a toad. 

 In any event it serves for the attachment of the muscles 

 on the inside, and they are thus protected, instead of 

 sheltering and protecting an inside bony framework as 

 in man and other vertebrate animals. 



It will be further seen, especially in the simpler 

 forms, that the body is made up of successive rings or 

 joints, more or less similar in the primitive types, often 

 very unlike in the higher orders, and that the legs also 

 are made up of a number of parts or segments. These 

 characters place the insects with that great section of 

 the animal kingdom known as Articulata, which includes 

 everything from an earthworm to a lobster, and more 

 narrowly restricts them to the Arthropods, which have 

 jointed legs, and thus exclude the worms; but still 

 leaves the lobster as a relative. 



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