66 THE ENTOMOLOGIST. 



left in the relaxing can for a few days before they are sufficiently 

 relaxed to set ; in the meantime many of them will most probably 

 have contracted mould. Now I venture to give a practical 

 suggestion to remove this difficult3% I damp the relaxing sand 

 as usual and place the insects upon it, and then pour over them 

 a few drops of benzine mixed with a little arsenic (which of 

 course should have been previously prepared, and well shaken 

 before use). I find that the benzine materially assists the process 

 of relaxation, and the arsenic contained in it prevents the growth 

 of that enemy, mould. — W. Harcourt Bath; Birmingham, 

 December, 1887. [A small quantity of naphthaline will be found 

 more effective in the relaxing pot. — Ed.] 



Fossil Lepidoptera, — Mr. Bell, in his interesting notes on 

 "Post-glacial Insects" (Entom. i), alludes to the absence of the 

 remains of Lepidoptera in deposits of the Post-glacial period. 

 That the Lepidoptera appeared ages before the period last 

 mentioned is evident from the numerous specimens obtained 

 from strata of Eocene and Miocene age ; and their absence from 

 Post-glacial deposits can only be explained, as Mr. Bell suggests, 

 by the unfavourable nature of such formations for the preservation 

 of soft-bodied animals. It would occupy too much space to 

 enumerate all the known fossil Lepidoptera, and my remarks 

 will, therefore, be confined to the Rhopalocera, of which less than 

 a dozen have been described. From strata of Upper Eocene age, 

 near Aix in Provence, five butterflies are known, viz., Neorinopis 

 sepulta, Lethites reynesi, Collates proserpina, Thelites riLininiana, 

 and Pamphilites abdlta. The two first-named belong to the 

 Nymphalidfe, the third and fourth to the Papilionidse, and the 

 fifth to the Hesperidfe. The remains of the plants on which the 

 larvae of these insects probably fed have also been found in the 

 same beds. In addition to the species above named, M. Daudet 

 has described the fossil larva of a species of Satyridse from the 

 neighbourhood of Aix. From the Lignites or Brown Coal of Rott, 

 near Bonn, of Lower Miocene age, Vcmessa vetula was obtained; 

 and this is the only butterfly known from the Lower Miocene of 

 Europe. The Lepidoptera from the marls of Radoboj in Croatia 

 (Middle Miocene) include three butterflies, viz., Eugonia atava, 

 belonging to the Nymphalidse, and Mylothrites pluto and Pontia 

 freyeri, belonging to the Papilionidse. From America only one 

 butterfly is known, viz., Prodryas persephone, which belongs to 



