464 MISSOURI STATE HORTICULTURAL SOCIETY. 



each stage of its existence, that only experience enables us to recog- 

 nize the various forms as pertaining- to the same individual ; and partial 

 when the insect retains essentially the same form and habit during life, 

 its successive stages of development being marked only by the acquisi- 

 tion of certain organs and appendages. 



The most familiar example of complete transformation is afforded 

 by an insect which in its first active state is a sluggish, worm-like cater- 

 pillar, feeding voraciously on herbage, and changing in due time to the 

 inactive, casket like chrysalis, which bears as little resemblance to the 

 larvae that preceded it as to the imago that shall ultimately escape from 

 it, viz., the broad-winged, bright-hued butterfly, instinct with graceful 

 activity, as it hovers over the flowers from which it sips its sole nourish- 

 ment, a dainty draught of nectar. Examples of partial transformation 

 are found in such insects as grasshoppers, locusts, true bugs, etc. 



The life of an insect begins with the embryo contained in an egg. 

 Instinct guides the parent insect in the placing of her eggs, so that her 

 progeny, as soon as hatched, find themselves surrounded with the kind 

 of food they require. The eggs of insects are of various forms — round, 

 oval, conical or disk-like. They are deposited singly or in clusters ; 

 sometimes openly exposed on the surfaces of leaves or stems, some- 

 times concealed with the utmost ingenuity. Those of many species 

 are beautifully colored or elegantly sculptured. The eggs of some 

 small insects which produce but few are proportionately large, while 

 on the other hand many large insects lay very minute eggs, but make 

 up in number what is lacking in size. 



The insect in hatching from the egg enters on its larval stage of 

 existence. This is the form in which all actual growth takes place, and 

 in which, as a consequence, the insect requires most food. It may, in 

 succeeding stages of development, assume different forms and acquire 

 additional members, but it never really increases in bulk. 



The larvre of the various kinds of insects differ so much in appear- 

 ance, and in many other respects, that it is difficult to give a list of 

 characters that are common to all. The typical form is more or less 

 worm like : i. e., cylindrical and elongate ; but the variations from this 

 type are exceedingly numerous, even among insects whose transforma- 

 tions are complete; while those that undergo only partial transforma- 

 tion do not conform to it at all. 



In the majority of larvre the thorax and abdomen are not distinct, 

 except that the first mentioned region is often provided with the rudi- 

 ments of legs. The latter are of a shelly texture, small and pointed at 

 the extremity, with three or four joints. They are six in number, and 

 are termed the true or thoracic legs, to distinguish them from the fleshy 



