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PSYCHE. 



ORGAN OF THE CAMBRIDGE ENTOMOLOGICAL CLUB 



EDITED BY GEORGE DIMMOCK AND B. PICKMAN MANN. 



Vol. II.] Cambridge, Mass., March, 1879. [No. 59. 



Geographical Distribution of North American 

 Coleoptera. 



SECOND ANNUAL ADDRESS OF THE PRESIDENT. 



Last year your president gave a sketch of the various con- 

 tributions to the Hfe-histories of our insects during the preced- 

 ing year. I shall speak only of the geographical distribution of 

 the Coleoptera ; my excuse must be a lack of sufficient time, 

 and a want of familiarity with the other groups. Any conclu- 

 sions derived from the study of the geographical distribution of 

 Coleoptera w^ill have more value than if derived from other 

 groups, because of the great number of species of Coleoptera, 

 and the fact that this group has been much more extensively 

 collected and studied in our region than any other. 



The increasing popularity of the theory of the continuity of 

 organic life from the earliest geological ages to the present time 

 has given a great impetus to the study of questions of distri- 

 bution, while at the same time every new fact in regard to dis- 

 tribution is important as tending to confirm or throw doubt on 

 the theory. 



So long as every species was supposed to be due to a special 

 creative act, questions of distribution were of very little in- 

 terest. It was as easy to conceive of the creation of the same 

 species in several places, at the same or different times, as to 

 conceive of the creation of several species in the same place. 

 As soon, however, as one is convinced that all the specimens 

 of a species are related to each other by descent from a com- 

 mon ancestor, and that all the species of a genus are also so re- 

 lated, and that when found in widely separated localities they 



