42 INTERNAL ANATOMY. 



ciously and the neglect of its powers of flight. Cer- 

 tainly its wings are in transition and comparatively 

 small through disuse, and its descendants, if it should 

 have any, might become like some females of the 

 cockroach tribe, the possessors of very inferior and 

 unlovely pads. 



We strongly advise teachers not to use this or any 

 theory in teaching immature minds. We give it be- 

 cause we are addressing mature minds, and know 

 that many of them will ask such questions and get no 

 reply. The use of a theory in teaching demands a 

 large knowledge of facts and a capacity to understand 

 and explain numerous exceptions, which bright pupils 

 are very apt to find. Immature minds ought to em- 

 ploy the time wholly in observing, the handling of 

 theory being not only beyond their grasp but injurious, 

 because it leads them to neglect the work which they 

 can do well for a game at speculative guessing. 



In the locust, as in most insects, the sexes are dis- 

 tinct. The male (PI. I., Figs, i, 2, 7, p. 10) is smaller 

 than the female (PI. I., Fig. 3, PI. II., Fig. 17, p. 38) 

 and is less abundant. In the autumn specimens of both 

 sexes can be easily collected, for they are found in con- 

 siderable numbers as late as November. The develop- 

 ment of the Rocky Mountain locust has been carefully 

 worked out and probably does not differ in essential 

 points from that of our yellow-striped locust, so that 

 we give it here.^ When the time of oviposition arrives, 

 the female makes a deep hole or burrow in the ground 



1 See Third An. Rep. U. S. EnL Com., 1880-82, Chap. X.; 

 First An. Rep. U. S. Ent. Com., 1877; T/ie Locust Plague in 

 the United States, Riley, 1877. 



