186 Psyche [December 



The work on Tertiary insects was largely based on specimens 

 from Florissant, Colorado, where Scudder himself made a very 

 large collection. He also collected from the White River deposits 

 on the Colorado-Utah boundary, and visited (Eningen, the famous 

 locality in Baden which may be said to represent Florissant in 

 Europe. Scudder's writings on Tertiary insects are so voluminous 

 that it is hardly practicable to review them in this article; but 

 attention must be called to the fossil butterflies from Florissant 

 and from Aix in France, and to the great work on the Rhyncho- 

 phora. In the course of the work, various important generaliza- 

 tions were made; these are now familiar to entomologists, and 

 need not be discussed in this place. The detailed descriptive work, 

 however, has not received the attention it deserves, and monog- 

 raphers of groups of living insects cannot be too strongly urged 

 to examine Scudder's writings, which will undoubtedly throw 

 important light on problems of descent, and especially on the 

 migrations of faunae. 



Scudder took great interest in the Quaternary insect-fauna, 

 describing 80 species of beetles from the Postpliocene and Inter- 

 glacial deposits of Canada, and three from Massachusetts. This 

 work was important in a number of ways, but perhaps most of 

 all as indicating the approximate rate of the evolution of species 

 in insects, proving that Coleopterous species, at least, are much 

 less permanent than those of plants.^ On the other hand, it is 

 seen that the specific changes taking place are comparatively 

 insignificant, and that for generic differentiation in insects, long 

 periods are usually required. From the Tertiary and Quaternary 

 work we conclude that in the rate of evolution, insects stand 

 between flowering plants and vertebrates. 



1 A very exact study of the preglacial flora of Britain was published by C. and E. M. Raid in 

 1908 (Journal of the Linnean Society, Botany). It was found that of 147 species, nearly all 

 were living, but a few apparently extinct. 



