10 Journal New York Entomological Society. [Vol. xx. 



tioned a circumpolar distribution must be assumed as an original con- 

 dition. In that respect I have especially in mind longilahris, 12- 

 guttata and purpurea, because each of these has an existing proto- 

 type in Siberia or Europe. On the contrary after considering many 

 of our species as emigrants from South America, and others as 

 survivors of former circumpolar forms, there remains a residue 

 which indicate in their characters no close relationship with the 

 species of other countries and must be regarded as originating 

 with us, at least in comparatively recent time. Such is evidently 

 the case with the genera Omiis and Arnhlychila, both peculiarly 

 our own and such also I conceive to be the case with those of our 

 species which do not range far enough north to indicate original 

 circumpolar relations or far enough south to indicate South American 

 affinities. Such for instance as rufivcntris, hirficollis, aiicocisconensis, 

 marginipciinis, and surely Icpida and gcncrosa. It is as reasonable to 

 assume a North American origin for some species as a South Ameri- 

 can for others and most unreasonable to assume that the one region 

 could have originated all and the other none. This subject has been 

 in my mind ever since a happy discussion in 1902 between Mr. Schaef- 

 fer, Dr. Horn and myself, in which Dr. Horn held strongly to the 

 idea of a South American origin, luidoubtedly true as to many but 

 I am convinced not as to all. 



In speaking of the origin of these species I do so in the sense of 

 their contemporaneous origin from preglacial species of the same 

 genus, delving into their comparatively recent history, rather than 

 into the first appearance of the genus on our earth. The evidence 

 afforded by the fossil Coleoptera of the Don beds near Toronto, in 

 which I understand many species are or may be referred to existing 

 genera, would not suggest that great structural changes have taken 

 place in tiger beetles since the glacial epoch ; and such similarities in 

 maculation as we observe in the European caucasica and our own 

 hirticollis, bearing in mind the former connection through Siberia, 

 may even suggest that in color and maculation little change has taken 

 place. 



The assumption of a South American origin for part of the 

 species, and of a circumpolar origin for the remainder, part of the 

 latter attaining their present characters on this continent before the 

 ice age, part roaming over this continent and Eurasia, would imply 



