FLORISSANT; A MIOCENE POMPEII 



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merely to the science of myrmecology, but to wider biological theories 

 as well. It is, indeed, through the examination of myriads of speci- 

 mens representing particular periods in the history of the world, that 

 we may expect to solve some of the most difficult questions of evolution. 

 Scudder noticed that among certain of the groups of fossil insects there 

 were particular tendencies observable throughout, notwithstanding the 

 'fact that the species belonged to different groups. Legs had grown 

 longer, or wing-cells had shortened, since the Miocene, and different 

 series, already at that time quite separate and free from crossing, had 

 been affected in the same manner. The same sort of thing was later 

 remarked by Professor Osborn in the teeth of extinct animals, and he 

 became convinced that there were fundamental predispositions to vary 

 in particular directions. Theories of this sort, if completely verified, 



Fossil Chestnut Leaf (Castancu doUchophyUu). Close to the leaf is also seen 

 a small freshwater shell (Phmorbis florissantcnsis). 



would greatly affect our ideas of the process of evolution ; but the chief 

 need at present is for more light, derived from more and more diverse 

 groups of animals. Hence the study of the fossil insects, at first seem- 

 ing of purely entomological interest, is likely to lead to results of the 

 first importance. 



While we thus search for trends of evolution, we note also the great 

 conservatism of insect types. It is well known that warm-blooded 

 animals have undergone great changes since the Miocene, one of them 

 being the evolution of man himself. In the case of the insects, how- 

 ever, the modifications have been slight indeed, even where these have 

 been driven far and wide by adverse changes of climate. 



We find, it is true, a fair number of extinct genera; types which no 

 longer persist in the modern world; but these appear to be merely those 

 which have died out, not the ancestors of any modern kinds. None of 



