BASIS OF CLASSIFICATION. 9 



only to a partial transformation. The parts of the legs are the 

 hip-joint, by which the leg is fastened to the body, the thigh, 

 the shank (tibia), and the foot, the latter consisting some- 

 times of one joint only, more often of two, three, four, or five 

 pieces {tarsi), connected end to end, like the joints of the 

 finger, and armed at the extremity with one or two claws. 

 Of the larvae that undergo a complete transformation, mag- 

 gots and some others are destitute of legs ; many grubs have 

 six, namely, a pair beneath the under-side of the first three 

 segments, and sometimes an additional fleshy prop-leg under 

 the hindmost extremity ; caterpillars and false caterpillars 

 have, besides the six true legs attached to the first three 

 rings, several fleshy prop-like legs, amounting sometimes to 

 ten or sixteen in number, placed in pairs beneath the other 

 segments. 



The abdomen, or hindmost, and, as to size, the principal 

 part of the body, contains the organs of digestion, and other 

 internal parts, and to it also belong the piercer and the sting 

 with which many winged or adult insects are provided. The 

 piercer is sometimes only a flexible or a jointed tube, capable 

 of being thrust out of the end of the body, and is used for 

 conducting the eggs into the crevices or holes where they are 

 to be laid. In some other insects it consists of a kind of scab- 

 bard, containing a central borer, or instruments like saws, de- 

 signed for making holes Avherein the eggs are to be inserted. 

 The sting, in like manner, consists of a sheath enclosing a 

 sharp instrument for inflicting wounds, connected wherewith 

 in the inside of the body is a bag of venom or poison. The 

 parts belonging to the abdomen of larvse are various, but are 

 mostly designed to aid them in their motions, or to provide 

 for their respiration. 



An English entomologist has stated, that, on an average, 

 there are six distinct insects to one plant. This proportion 

 is probably too great for our country, where vast tracts are 

 covered with forests, and the other original vegetable races 

 still hold possession of the soil. There are above 1,200 

 2 



