THE AMERICAN NATURALIST. [Vol. XXXVIII. 



degree constant, and that they may be homologized in the dif- 

 ferent groups, I beUeve to be very true. That they are second- 

 ary is equally true, and thus evidence drawn from a study of the 

 sclerites of the adult insect is insufficient to determine the primi- 

 tive segmentation and the related question as to the compound 

 nature of the segments. 



