FOSSIL INSECTS 61 



have to provide themselves with much larger nets should the thousands 

 of past generations of insects celebrate a joyous resurrection, for the 

 size of these Jurassic representatives was from four to five times that 

 of many forms now existing in the Danube region. 



But these fertile years were apparently preceded by others more 

 barren. At least this impression is gained when we contemplate the 

 swarms of insects that lie buried in a stage still lower — the Lias, or 

 black Jura. The discovery of some rich localities in Switzerland, in 

 Mecklenburg and in England, for instance, have yielded almost abso- 

 lutely dwarf species. On the average, these forms were even smaller 

 than those inhabiting the same regions to-day; truly starved species. 

 In fact, at that time there were as yet no butterflies, few Hymenoptera, 

 and no other striking insects. The beetles and gnats found were small 

 and insignificant. On the other hand, caddice-flies and scorpion-flies 

 were abundantly .represented, the latter of which now play only a 

 limited part. There were also dragon-flies of moderate dimensions, 

 bugs and small cicadas similar to our frog-hoppers; grasshoppers and 

 locusts, and the ever-present cockroach as well. 



From the long Triassic period that stored up a large part of the 

 material from which the imposing dolomite towers were subsequently 

 formed, we as yet unfortunately know only some insignificant beetles 

 and Neuroptera. Hence, we can turn at once to that very ancient 

 period called the Paleozoic. On important but purely material 

 grounds, this epoch stands very close to mankind in general, since it 

 includes the most valuable coal deposits, the mining of which has 

 materially aided our present studies. In and near the coal in many 

 places in Europe and North America has been found a great number 

 of impressions of insects whose investigation furnishes us with an 

 entirely new world of forms. 



Although in the upper beds of this period no more beetles and 

 Neuroptera are found, yet caddice-flies and scorpion-flies, gnats and 

 locusts, too, are wanting. So much the more do the cockroaches in- 

 crease ! May-flies and stone-flies were already represented, and Hem- 

 iptera as well, but of a form that it is not known whether they should 

 be pronounced cicadas or bugs. 



In addition we also find insects that it may not be possible to 

 arrange in the established classification of living forms, although 

 affinities with the latter are undoubtedly to be recognized. The deeper 

 we descend into the coal period, these forms more and more increase 

 in number, while modern types gradually become less and less frequent. 

 It may therefore be concluded that in the Carboniferous forms the 

 direct ancestors of many of the insect groups previously mentioned are 

 to be sought, and hence corresponding names have been chosen for 

 them: as Protodonata, the ancestors of the Odonata, or libellids; 



