72 FOSSIL BUTTERFLIES. 



obtains in New Guinea or New Grenada, countries the least favored in this" 

 respect. 1 The proportion of the Gramineae and Cyperacere to the whole of the 

 Phanerogamia in Europe of to-day is, probably, about the same as in the United 

 States (more than seventeen per cent.) and much greater than in the East Indies. 

 The limited number of known fossil butterflies does not give great weight to any 

 general considerations based upon them, but it may at least be worth while to 

 remark that Aix, in Eocene times, had, in the point referred to, an assemblage of 

 plants much better comparable with the East Indian flora of the present day than 

 with the modern European flora, the proportion of known Gramineae, etc., to the 

 Phanerogamia being five per cent., while the proportion of its grass-feeding but- 

 terflies to the other rhopalocerous Lepidoptera is sixty per cent. To judge simply 

 by the catalogue of the East India Museum, the only authority upon East Indian 

 butterflies extant, the present proportion of gramnivorous to non-gramnivorous 

 butterflies is as 1 : 5 - 2, while in Europe it is as 1 : 3. Eocene Aix, then, had a 

 European proportion of Satyrids, composed, as will be seen, of species of an In- 

 dian aspect, feeding upon plants essentially temperate, but, as in tropical countries, 

 numerically unimportant. 



The Danai, to which the fourth species from Aix ( Collates Proserpina) belongs, 

 feed almost exclusively upon Leguminosse, and these have recently been found in 

 great abundance at Aix. Coiint de Saporta enumerates one species each of V Tri- 

 folium, Caragana, Ervites, Sophora, Micropodium, Cercis and Gleditsehia, two of 

 Phascolites and six of Csesalpinites, belonging to the Papilionacea?, besides nine 

 Acacias and a Mimosa of the Mimosese, and four species of uncertain relations; 

 making a series larger than he has found in any other family. 2 



Of these, two species of Phaseolites, one of Sophora, eight of Acacia and two 

 of Leguminosites are specified as coming from the lower beds, where Coliates 

 itself is found. But Coliates is most closely allied, as we have said, to a group of 

 Indian forms, and the food plants of their caterpillars is almost wholly unknown. 



La proportion de.s (irjiniiiiees rolativrmrnt ;iu totnl des flores intertropirnk's actnelk'S de 1'anrion et ilu nouvcau continent, 



Phaoerogames, qul est de 4'5 BUV 100, eat en rapport nvrr, h-s inin- inais elles atteignc 



im.i relatife de cette famHlc, tele qu'on u-s niiTrve a la Xomvlie- scmblr <les I'haner 



( .nim'<c! et a la NouvirlliMJrenadr." Saporla. I'" 1 . <'it.. 2!i3. aver relic de li sil 



2'' Dans la lion- tics ^yp--''* <!'\i\. inm-M-ulrim-nt ICH Lo^n- 'lans certaines v<-gU 



iiiin*-ii.-f> oiTiipt-nt It- prnniiT ran^. conimo daiiH la pluparl dc.-A Saporta, loc. cit., 292. 



it inir proportion <le 13 pour 100, pour 1'cu- 

 j*:i nies, proportion parfaitement en rapport 

 100 qui cst fmnuMitt', Felon M. de Cnntlniic. 

 ns cluuule^, tellcs qm- I'IUMM. Ic Cmi^o, etc." 



