1919] Distribution of Insects 3 



keeping with those worked out by Merriam* and other mam- 

 malogists and ornithologists and substantiated by the botanists. 

 Certain of the detailed results secured have, however, been 

 found to be at variance with those found by others or to have 

 previously not been worked out. 



In general the insects which are considered to be of northern 

 origin now occupy the northern and more mountainous portion 

 of the territory. The greater portion of this, such as that 

 including the lower levels of the Aleutian Islands, particularly 

 the eastern ones, the southern margin of the Alaska Peninsula, 

 southeastern Alaska, the western part of British Columbia 

 as from the Selkirks west, Washington and Oregon west of the 

 Cascade Mountains, and the wet and cool coastal strip of 

 California, extending as far south as middle Monterey County, 

 now supports a fauna which I have called the Vancouveran. 

 The name Transitional as applied to this fauna, though generally 

 used by previous workers, I consider misleading. The fauna 

 is a pure one, in fact one of the purest in North America. It 

 contains many peculiar groups of insects, some almost in their 

 entirety, and is especially rich in such families as the Carahidce, 

 Staphylinidce, ElateridcB and certain groups which are more or 

 less closely associated with the coniferous forests. The following 

 are good representatives: the genus Omus, the subgenus 

 Brennus of Scaphinottis , the impunctate division of Pterostichus, 

 Zacotus, Metrius, Promecognathus and the American representa- 

 tives of Trigoniiriis. Rosalia funehxis Mots, is also a char- 

 acteristic member of this fauna, but it extends considerably 

 beyond its confines. The fauna has existed in approximately 

 its present territory from the Tertiary period and no doubt 

 from well back in that period, being in fact a Tertiary fauna 

 which has come down to us in a pure state. Many of the 

 species that it contains have probably not changed during this 

 long series of years but others have, some having become 

 broken up into races which, becoming more and more isolated, 

 have formed new species, subspecies, and so forth. As a result, 

 the fauna is not the same throughout its extent. It gradually 

 divides itself up into several subfaunas. 



* The Geographical Distribution of Life in North America with Special 

 Reference to Mammalia, by C. Hart Merriam, Proceed. Biol. Soc. Wash. Vol. VII, 

 April 13, 1892. 



