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So far as I can ascertain, the most recent discovery of fossil 

 insects in this part of France has been made by M. Ch. Brongniart, 

 who, in the " Bulletins de la Societe Geologique de France " for 

 last year (1876), describes a new species of a Dipterous insect, 

 which he has referred to the genus Frotomyia and named P. Oustaleti 

 in recognition of the very imj^ortant contributions to our know- 

 ledge of the fossil insect fauna, of France, made by M. Oustalet. 



The genus Frotomyia, of Heer, observes M. Brongniart, 

 contains no living representatives, although it wasnumerously 

 represented during the Tertiary period, nearly 40 species referable 

 to it having been described by Heer, Von Heyden, and Oustalet. 

 According to M. Brongniart, this new species was discovered 

 in the calcareous Marl of the inferior Miocene formation of 

 Chadrat in Auvergne. It differs from all previously described 

 species in the distribution of the nervures, and appears most 

 closely allied to P. Jnannis and P. Bucklandi. 

 Upper Eocene. 

 Nowhere in the Continental formations of this period, with 

 the exception of (Eningen, have fossil insects been discovered in 

 greater abundance than at Aix, in Provence. The town of Aix 

 is situated in the lowest part of a deep valley, the immediate 

 flanks of which are composed of a thick fresh- water formation 

 lying unconformably upon strata of Jura Limestone. The 

 Fresh-water series consists of white and grey calcareous marls 

 calcareo siliceous grits, and beds of gypsum. 



M. Marcel de Serres was the first to make known to the 



scientific world the occurrence of insects in these gypseous marls. 



In his "Geognosie des terrains tertiaires," he enumerates 



about eighty genera from this locality, comprising the following 



viz. : — 



Coleoptera 20 genera. 



Orthoptera ... ... ... 6 



Hemiptera 14 



Neuroptera ... ... ... 2 



Hymenogtera 9 



Lepidoptera ... 4 



Diptera 20 



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