4 A COMPARISOX OF THE FOSSIL INSECTS 



also from those of Aix, of the Rhenish peat-deposit, of 

 CEningen and Radoboj ; and from that of amber, differing 

 not only in species but in genera. 



It had so often been announced that the mass of the 

 Solenhofen fossil Libellulce were of the genus ^schnay that 

 I was hence the more surprised, amongst all the numerous 

 specimens I examined, to see only a single ill-preserved 

 specimen of an ^schna ; nearly all the remaining specimens 

 being Gomphidce or Calopterygidce. Amongst the numerous 

 Solenhofen insects there is this remarkable circumstance, that 

 at a first glance an insect seems in general appearance to 

 accord precisely with some existing genus, but, on a closer 

 examination, we find such distinctive characteristics and so 

 many of them that the insect cannot possibly be placed in the 

 genus to which it, at first sight, seemed referable. As far as 

 I can at present perceive, almost all the Solenhofen insects 

 will necessitate the construction of new genera, which, however, 

 will often furnish connecting links between some of our 

 existing genera. 



If we turn our attention to the Odonata, which form so 

 large a portion of the insect Fauna of the Bavarian strata, and 

 pieces of the wings of which seem also not uncommon in the 

 English strata, we find a remarkable and apparently inexpli- 

 cable contrast between the Fauna of the English secondary 

 strata and the Fauna of CEningen and Radoboj. Whilst here, 

 as also in the Rhenish peat, larvse and pupae o? Lihellulce are 

 found in great numbers, many often lying together, the 

 perfect insects being proportionally scarce ; in the Solenhofen 

 and Eichstadt deposits Libellid<B are precisely the most 

 plentiful specimens (forming one-third of all the insects), and 

 on the other hand up to the present time not a single larva or 

 pupa has been found. 



