﻿OF THE STATE ENTOMOLOGIST. 



81> 



[Fig. 22.] 



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 cater- 

 pillar, curled within its egg-shell, has room enough to move its jaws 

 and eat its way out ; the egg-coverings of many insects are so delicate 



and frail that the mere swelling of 

 the embryon affords means of es- 

 cape-; those of others so construct- 

 ed that a door flies open, or a Md 

 lifts by a spring, whenever pressure 

 is brought to bear : in some, two 

 halves open as in the shell of a 

 muscle; whilst in a host of others 

 the embryoniis furnished with a spe- 

 cial structure, called the egg-bur- 

 ster, the office of which is to cut or 

 rupture the shell, and thus afford 

 means of escape. But our young lo- 

 cust is deprived of all such contri- 

 vances, and must use another mode 

 of exit from its tough and sub-elastic 



Egg OF Rocky Mountain Locust:— a, showing . -kt i_ i- i ^i 



sculptuve of outer shell; 6, the same very priSOU. JN ature aCCOmpllSheS the 

 highly magiiilled; c, the inner shell just before 



hutching; rf,e, points where it ruptures. ^^^q q^^ j^ many different Way s. 



She is rich in contrivances. Every one who has been troubled by it 

 must have noticed that the shanks (tibias) of our locust, as of all the 

 members of its family, are armed with spines. On the four anterior 

 legs, these spines are inside the shank; on the long posterior legs, 

 outside. The spines of ihe hind shanks are strongest, and the termi- 

 nal ones on all legs stronger than the rest. There can be no doubt 

 that these spines serve to give a firm hold to the insect in walking or 

 jumping ; but they have first served a more important prenatal iDur- 

 pose. 



When fully formed, the embryon is seen to lie within its shell, as 

 at Fig. ^2, c. The antennas curve over the face and between the jaws, 

 which are early developed, and, with their sharp, black teeth, reach 

 onto the breast. The legs are folded up on the breast, the strong ter- 

 minal hooks on the hind shanks reaching toward the mesosternum. 

 Now the hatching consists of a continued series of undulating con- 

 tractions and expansions of the several joints of the body, and with 

 this motion there is slight but constant friction of the tips of the 

 jaws and of the sharp tips of the hind tibial spines, as also of the tarsal 

 claws of all the legs against the. shell, which eventually weakens 



