244 



S } ~S TEMA TIC ZOO LOG Y. 



thread-like; ocelli are always present; the pro thorax moves 

 freely on the mesothorax; the abdomen is ten-jointed, and 

 it usually bears on its tenth somite movable cerci; the 

 ovipositor is large and cannot be withdrawn into the 

 abdomen; the anterior wings serve as covers for the second 

 pair, and these last are folded longitudinally, when at rest, 

 like a fan. 



Besides these points, which should have been made out 

 by the student, there is another feature not readily dis- 

 covered in the classroom. The young Orthopteran hatches 

 from the egg with all the legs and segments of the adult, 

 which it resembles much in general appearance, except in 

 the following particulars: it is smaller in size, with a dis- 

 proportionately large head, and it lacks the wings character- 

 istic of the full-grown form. It is most voracious, and 

 with much eating increases rapidly in size. But since it is 

 enclosed in a hard outer wall, incapable of growth, it has 

 frequently to cast off this non-elastic 'skin' and to grow 

 a new one, larger than the old. This molting is accom- 

 plished by a splitting of the old skin down the back, and 

 from this hole the animal draws itself, and now, its skin 



FIG. 69. Young grasshopper with the wings just beginning to appear 



After Emerton. 



being soft, it can readily increase in size. Gradually, 

 however, the skin becomes thicker and harder, and the 



