74 



The Rocky Mountain Locust. 



[Fig. 10.] 



and gives the pale, cream-yellow color, is seen by aid of a 

 high magnifying power to be densely, minutely and shal- 



lowly pitted ; or, to 

 use still more exact 

 language, the whole 

 surface is netted with 

 minute and more or 

 less irregular, hexag- 

 onal ridges (Fig 10, 

 a, b). It is a mere 

 - covering of excreted 

 matter, similar in na- 

 ture to the mucous 

 matter, already de- 

 scribed, which binds 

 the eggs together. 

 The inner layer (or 

 chorion} is thicker, of 

 a deeper yellow, and 

 perfectly smooth. It, 

 - also, is translucent, so 



ing sculpture of outer shell: 6. the same, very r l-,q r r,« trip Vintnliincr 

 highly magnified , c. the inner shell, just before tliat » aS tne ^atcnmg 

 hatching ; cZ, e, points where it ruptures period approaches, the 



form and members of the embryon may be distinctly dis- 

 cerned through it. The outer covering is easily ruptured, 

 and is rendered all the more fragile by freezing ; but the 

 inner covering is so tough that a very strong pressure 

 between one's thumb and finger is required to burst it. 

 How, then, will the embryon, which fills it so compactly 

 that there is scarcely room for motion, succeed in escaping 

 from such a prison ? The rigid shell of the bird's egg is 

 easily cracked by the beak of its tenant ; the hatching 

 caterpillar, curled within its egg-shell, has room enough 

 to move its jaws and eat its way out ; the egg-coverings 



