84 Annals Entomological Society of America [Vol.1, 



mologists. It is evident that if systematists would keep their 

 field of work abreast with the movements in other lines it will be 

 necessary to take into account all the factors that may seem to 

 give evidence as to affinity. 



It should be clearly appreciated, however, and I think will be 

 recognized by entomologists as quickly as any body of naturalists 

 that habit is only one factor, that while it has had a determining 

 influence in producing structure it has so frequently occurred in 

 parallel lines in different groups that fundamental structures 

 based doubtless on the more remote habit, must be taken into 

 account. To ignore this would carry us back to such inconsist- 

 encies as placing whales with fishes, or the parasitic insects, fleas, 

 lice, bird-lice, etc., in one group, Aptera. We must fully deter- 

 mine the significance of the deeper adaptations as re\-ealed in 

 more finidamental character along with the superficial modifica- 

 tions of more recent habit. 



