INSECTS. 13 



the order Neuroptera, as regards the number of individuals, is 

 much more predominant at (Eningen than in the existing fauna 

 of any part of Europe. The most abundant insects, as regards 

 the number of both species and individuals, are the beetles ; and 

 we may say that, on the average, out of two specimens found at 

 (Eningeii one belongs to this order. Among the Hymenoptera 

 the ants occur most abundantly, and among the Diptera the 

 gnats and midges. 



Of land-insects, only those have remained which were carried 

 down into the lake by running water and driven from the shore 

 over the lake, and which there perished. The winged insects 

 were more exposed to this danger than the wingless ones ; the 

 latter, consequently, occur but rarely. Thus, of the ants we 

 find the winged males and females, but seldom the wingless 

 workers. Of the beetles we find many lying with outspread 

 wings, exactly in the position which they assume when they have 

 fallen into the water and are endeavouring to save themselves by 

 extending their wings (fig. 255). Nevertheless the wingless 

 land-insects are not entirely deficient. Prof. Heer has obtained 

 from QEningen a caterpillar, larvae of grasshoppers, and two or 

 three worker ants ; and indeed the spiders and the woodlouse, 

 already referred to, prove that the (Eningian collection of annu- 

 lose animals is by no means limited to winged insects acciden- 

 tally carried by the wind over the lake. The wingless forms 

 probably fell from the bank into the water, perhaps from trees 

 which overshadowed the lake ; but they were also swept into the 

 lake by the brooks. Of the insects which fell into the water, 

 only those have been preserved which were quickly covered by 

 the mud and thus saved from destruction. Aquatic insects be- 

 longing to the Lake of (Eningen are very numerous, and are 

 found in all stages as larvae, pupae, and adult animals. Most of 

 the aquatic insects have no doubt been destroyed without leaving 

 any traces ; but many were so rapidly enveloped by the fine cal- 

 careous deposit that they have not merely produced an impres- 

 sion in it, but even the organic substance has been preserved. 

 By this rapid covering, the softest midges are so admirably pre- 

 served that, under the microscope, the hairs on their legs and 

 wings can be recognized, and the colours of the land- bugs can 

 still be ascertained. 



