112 ORTHOPTERA. 



which has been stated very often in other publica- 

 tions. This in a few words is as follows : In any 

 series of forms evolving through time, new character- 

 istics are acquired by each species or new form. 

 These novel characteristics show a strong tendency, as 

 a rule, to reappear in the new forms subsequently 

 evolved at earlier stages in the development of 

 individuals than those in which they first appeared. 

 This process, long continued, finally causes the later 

 acquired, stronger, and more suitable characteristics 

 or modifications to crowd upon and replace the older, 

 ancestral, and useless characteristics of the younger 

 stages. When this process is carried to an extreme, 

 the later acquired adaptive characters, as in the locust, 

 may absolutely supplant the older ancestral stages. 

 The law of acceleration in development, as this has 

 been called, is, therefore, adequate to meet all objec- 

 tions arising from such cases, and amply accounts for 

 the absence of the Thy sanuri form larva in the salta- 

 torial Orthoptera, and other similar cases where the 

 adult characters of a group appear in the larval stages 

 and replace the hereditary larval characters. 



