24 THE CANADIAN ENTOMOLOGIST. 



Whitneyi and residua. We have seen, that the more correct determina- 

 tion of the moths alone is a matter of scientific experience, inborn feeling, 

 in short of tact which comes alike from long work and genius for the study. 

 The check to all such determinations of the perfect insects is breeding 

 from the egg. 



In the North American fauna, we also have the European genus 

 Scopelosoma ; in Europe with one constant form, in North America with 

 several closely allied. How thankful I am, that Mr. Thaxter has bred our 

 closely allied species, so that no opinion formed from the imagines alone 

 is now worth having or recording. 



As the result of our comparison, we see the fact that species tend more 

 to vary, to wander off into new forms in North America ; whereas, in 

 Europe, they have a greater setness, or fixity in their appearance. It 

 would seem as if the faunal changes in America had been greater, influ- 

 enced by physical causes, the chain of longitudinal mountains, the land 

 connection of the tropics, the course of the winds of the gulf stream, all 

 the phenomena of climate and temperature. The probability is, that the 

 European species are nearer the old circumpolar pre-glacial forms ; 

 that in most cases the North American forms have made the variation, the 

 step in a new direction. 



Species by species, genus by genus, must these comparisons be made, 

 so that we may unroll the probable past of our butterflies and moths. The 

 life-histories must be known and compared. Work like that done by Mr. 

 W. H. Edwards, Mr. Thaxter, Prof French, Mr. Beutenmuller and others 

 must be encouraged. Some papers by Mr. Moffat, on the question of 

 species and variety naming, recommended themselves to me greatly. At 

 the risk of repeating myself, I maintain that, as an entomologist, we are 

 here to discriminate, not to lump ; our work is to talk about and illustrate 

 the differences we find in insects. 



An intelligent resolving of the study into its different phases is much 

 needed. While with patience, the fine work of discriminating the forms 

 is being carried on, the labour of comparisons, for the purpose of aiding the 

 solution of wider questions, should not be neglected. There is enough to 

 do, and I am glad to see, as the years go by and fresh workers come into 

 our field, that there will be enough to do it. It is the pursuit of truth that 

 j§ always new and interesting. 



