INSECTS. 17 



also two species of Aphides, among which the ladybirds and 

 wasp-flies may have taken up their abode. Aphides furnished 

 honey-dew for ants, which no doubt obtained it from them in 

 the same way as their relatives of the present time. The large 

 species of Cercopis found at (Eningen probably also supplied 

 saccharine juices for ants like their existing representatives in 

 warm climates. 



One gadfly has been found of the family of Tabanidse. Prof. 

 Heer has obtained from (Eningen thirty-three species of dung- 

 beetles, of which nineteen belong to the LamellicornSj which live 

 not only in but upon the excrements of Mammalia, and fourteen 

 to families (Histeridse, Oxytelidae, and Staphylinida3) similar 

 species of which dwell in excrements and carrion, for the purpose 

 of chasing and feeding on the larvse of the true coprophagous 

 insects. From the analogy of existing species we may indicate 

 even the genera of mammalia, the existence of which is betrayed 

 by these insects. Most of the species of the genera Copris, 

 Onthophagus , and Gymnopleurus that we know from CEningen 

 represent living species which live chiefly or exclusively in the 

 fresh excrements of horned cattle, and therefore presuppose the 

 existence of such animals, although the remains of cattle have 

 not yet been discovered. The genera Oniticellus and Geotrupes 

 (allied to the Scarabaus) lead to the supposition that animals of 

 the horse race lived in the forests of CEningen. A quadruped 

 of this kind (Hipparion gracile) is known in Switzerland. 



If we compare the (Eningian insect-fauna with that now 

 existing we find in it numerous peculiar types. Prof. Heer is 

 acquainted with 44 peculiar genera, 21 of them belonging to the 

 Coleoptera, 6 to the Neuroptera, 6 to the Diptera, 11 to the 

 Khynchota, and 1 to the Orthoptera. They include 140 jspecies, 

 many of which were among the most abundant and widely dis- 

 tributed of the insects. But by far the greater part of the 

 fauna must be ranged under existing genera ; and many of the 

 species are so nearly allied to living forms that they are probably 

 to be regarded as the ancestors of the latter. Prof. Heer calls 

 them homologous species. Most of these species belong to 

 genera at present distributed over both the Old and the New 

 World. There are in the CEningian fauna 180 of such genera, 

 of which 114 belong to the Coleoptera, Of the latter, two 



VOL. II. C 



