70 FOSSIL BUTTEKFLIES. 



COMPARATIVE AGE OF FOSSIL BUTTERFLIES. 



All the well determined fossil butterflies come from one of three localities, 

 Aix, Rott and Radoboj, all belonging to the tertiaries. of Europe. Others are 

 reported, as will be seen further on, to have been found in Prussian amber; and it 

 is not in the least improbable that they have been or may be. These would be of 

 about the same age as the oldest of the others, those of Aix. Of the Aix fossils, 

 which belong to the upper Eocene, or to speak more definitely, the Ligurian, 

 Neorinopis sepulta, Lethites Reynesii, Thaites Buminiana and PampMlites abdita 

 (the first described by Boisduval, the rest by myself) come from the calcareous 

 marls of the g3q3sum quarries, the only bed in which insects had been found when 

 visited by Messrs. Murchison and Lyell in 1829. Collates Proserpina, however, 

 described here for the first time, was taken from strata beneath these, and there- 

 fore, at least until we have more precise knowledge concerning the remains of 

 butterfly larvae in amber, may be considered the oldest known butterfly. Count 

 de Saporta writes me concerning this fossil, the discovery of which is due to him, 

 as follows: — "Cette empreinte ne provient pas des platrieres meme, c'est a dire des 

 galeries qui servent a I'exploitation du Gypse; mais d'une assise ou groupe de 

 couches immediatement inferieure. Yous verrez cette provenance indiquee pour 

 un grand nombre de mes especes; dans ce cas, elles ue proviennent par des ouvriers 

 mais je les ai recueillies moi meme en suivant les lits sur les points ou ils affleurent 

 au dehors." 



The next in order, approaching recent times, are the lignite beds of Rott in 

 the basin of the Rhine, which belong to the Aquitanian or the upper part of the 

 lower Miocene. Thanatites vetula (described by Hayden) is the only butterfly 

 known from this division of the Tertiaries. 



The most recent beds containing fossil butterflies are the lacustrine deposits 

 of Radoboj in Croatia, Austria. These belong to the Mayencian or lower portion 

 of the middle Miocene, and have furnished Eugonia atava, Mylothrites Pluto, 



