'J A COilPARISOX OF THE FOSSIL INSECTS 



at the splendid preservation of many of the specimens. One- 

 third of the entire collection is Libelhdce, another third con- 

 sists of Orthoptera and Semiptera, especially gioantic 

 species of 13elosfoma, Pynolampos and Nepa the remaining 

 third consists of Coleoptera, Hymenoptera and Diptera. 



On comparing the insects of Solenhofen and Eichstadt 

 with those of England, there appears in the first place a 

 difi"erence which may possibly admit of interesting inferences: 

 the insects of the Bavarian strata are almost universally 

 preserved entire; wings, legs, head and antennse are in their 

 proper places ; most of the LihellulcB have their wings ex- 

 panded. He who has noticed, on the sandy shores of the 

 Baltic, how depositions of insects are now taking place, will 

 admit that tlie insects of the Solenhofen strata were already 

 dead when deposited. 



The insects would be, as now, driven by the wind into the 

 sea, thrown on the shore dead or dying, and there gradually 

 covered with sand by the rippling waves. That this process 

 took place extremely graduall}^ and slowly in the Solenhofen 

 strata is evident also from another circumstance; for we 

 frequently find the cavities of insects, the head, thorax and 

 body, filled up with regular crystals of calcareous spar. 

 Hence the pressure of the stratum overlying the insects must 

 have been very slight, when such delicate parts as the 

 abdominal segments of a dragon-fly could oppose resistance 

 for a sufficient length of time to admit of the formation of 

 crystals. 



Naturally there do occur, here and there, in the Solenhofen 

 strata impressions of insects obtained in a different way, which 

 admit of the idea of a very heavy pressure from the super- 

 incumbent strata, yet these specimens are scarce and form 

 only a small proportion of the entire number. 



