170 THE CANADIAN ENTOMOLOGIST. 



opinion, a distinct genus from the presence of a claw on the front tibiae ; 

 the species have hairy eyes and otherwise generally agree with the very 

 numerous forms of the genus Mamestra. I have called the new genus 

 Copimaviestra, and described our Western species as C. Occidenta. So 

 wide a geographical separation as that of these two species, which, in 

 structure as well as markings, agree so closely, must have a deeper reason 

 and in my opinion points conclusively to a former common habitat which 

 has become disturbed by climatic and geologic change. 



We shall have to leave Entomology and go back into past geologic 

 epochs to explain the existence in our North American moth fauna of this 

 large number of forms with varying European affinities. Imaginative 

 persons have supposed the existence in former times of an Atlantic con- 

 tinent now submerged and which bridged the chasm of the waves. The 

 myth of the Atlantis has been furbished anew and on an immense scale 

 by certain writers under the inducement of the facts supplied by the dis- 

 covery of a plateau at the bottom of the Atlantic Ocean by the soundings 

 of H. M. S. Challenger, in its famous voyage of oceanic discovery around 

 the world.* 



It is sure that there was formerly a warm climate in the arctic zones 

 during the Tertiary and preceding geological age. This was a certain 

 measurable time ago, when the circumpolar regions had a warm average 

 temperature, with no winter, and the probable identity of the fauna ex- 



* I print here the following note received from the lamented Naturalist, R. von 

 Willemoes-Suhm, after whom I named the now well known genus of eyeless Crustacea 

 (found in the Atlantic at great depths by the Expedition) : — 



" Challenger, Yeddo, May 7th, 1875. 

 "My Dear Prof. Grote, — 



" There can be no doubt, I think, that Prof. Thompson will allow me to put aside 

 specimens of WiUeniocsia when we come back to Europe. Just now they are all packed 

 away and sent home, where the bottles remain unopened until we come back, which 

 will be in about a year's time, and I shall then be very happy in sending you the desired 

 Crustaceans. I am, with great respect, your obed't serv't, 



"(Signed) R. von Willemoes-Suhm. 



"To Prof. Aug. Radcuffe Grote, Buffalo, N. Y." 



This was the second and last note that I received from this enterprising Naturalist, 

 who died on board the Challenger shortly after, and before the ship left the Japanese 

 waters. So we may hope to get safely back home from our journeys and never see it 

 again ! 



