XXXI. 



BUTTERFLIES OF THE PAST 



Fossil butterflies are the greatest of rarities. 

 Tliey occur only in tertiary deposits, and out of the 

 myriads of objects that have been exhumed from 

 these beds in Europe and America less than 

 twenty specimens have been found. The great 

 body of these deposits is of course of marine 

 origin, but at least thirty thousand specimens of 

 insects have been recovered from those beds which 

 are not marine. Over fifteen thousand insects 

 from the one small ancient lake of Florissant, high 

 up in the Colorado Parks, have passed through 

 my hands, yet I have seen from there but eight 

 butterflies. Each of these belongs to a genus dis- 

 tmct from the others, as is also the case with all, 

 or all but one, of the butterflies found at Radoboj, 

 at Aix, and at Rott in the European tertiaries. 

 With two (European) exceptions, each represents 

 an extinct genus, and these two exceptions, Eugo- 

 nia and Pontia, are genera found to-day both m 



