272 BUTTERFLIES 



found at Aix, it is found in other European terti- 

 ary deposits, and according to the late Marquis 

 Saporta, the principal student of the fossil plants 

 of Aix, " Ce genre devait y exister." 



There are left the two Hesperidae, — a family 

 not represented in the American rocks. One of 

 these, Thanatites from Rott, belongs to the tribe 

 Hesperini and is closely related to Thanaos, a 

 genus found in the north temperate zones of both 

 •hemispheres, but vastly more developed in the 

 New World, which has at least four times as many 

 species as the Old, some of them extending into 

 the sub-tropical regions; the adjacent genera are 

 purely American, although tropical or sub-tropical, 

 and therefore Thanatites looks toward sub-tropical 

 North America for its prevailing affinities. En- 

 tirely the same is the case with Pamphilites of 

 Aix, a butterfly belonging to the other tribe of 

 Hesperidae. The food plant of both these butter- 

 flies was very probably Leguminosae, which occur 

 in abundance both at Eott and at Aix. 



The allies therefore of nearly one half of the 

 European fossil butterflies are to be looked for in 

 the East Indies ; of one third of them in America, 

 and especially sub-tropical America ; of the remain- 

 der, at home; but, as among mother insects and 



