INCOMPLETE METAMORPHOSIS. 



35 



these. Thus the young locust resembles the adult 

 in form to a great extent, except that it lacks wings ; 

 and the same thing is true of crickets, bugs, and 

 many other insects. 



Those insects which, like butterflies, millers, bee- 

 tles, and flies, undergo a complete change of form 

 while getting their growth are said to undergo a 

 complete metamorphosis. 



Insects which, like locusts, crickets, and bugs, do 

 not change greatly in form except by the gradual 

 growth of wings are said to undergo an incomplete 

 metamorphosis. 



Let us study more carefully the changes of an 

 insect with an incomplete metamorphosis. 



1. Pin the specimens that were collected on the 

 last excursion. If some are too small to pin, mount 

 them on cardboard points. 



2. Select those that were collected to illustrate 

 the changes in form from the very young insect 

 without any wings through the different stages of 

 wing-growth up to the adult insect. 



3. Determine how many stages of growth are 

 represented by these, and place together the speci- 

 mens illustrating each stage. The young of insects 

 that undergo an incomplete metamorphosis are 

 termed nymphs. 



4. Make an outline drawing of the thorax and 

 wings, when they are present, of each stage. Draw 

 either the dorsal or a side view, whichever will show 

 best the development of the wings. 



