chap, xxi.] INSECTS. 469 



Longicorns of the Tropics, are almost as well known as those of 

 the Temperate Zones, the Staphylinidse, the smaller Elateridae, 

 and many other obscure and minute groups, are very imperfectly 

 represented from extra-European countries. I therefore propose 

 to examine with some care the distribution of the Butterflies, 

 and the Sphingina among Lepidoptera, and the following large 

 and well-known families of Coleoptera : — Cicindelidse, Carabidse, 

 Lucanidse, Cetoniidae, Buprestidse, and the three families of Lon- 

 gicorns. These families together contain over 30,000 species, 

 classed in nearly 3,000 genera, and comprise a large proportion 

 of the best known and most carefully studied groups. We may 

 therefore consider, that a detailed examination of their distribu- 

 tion will lead us to results which cannot be invalidated by any 

 number of isolated facts drawn from the less known members of 

 the class. 



Range, of Insects in Time. — In considering how much weight 

 is to be given to facts in insect distribution, and what inter- 

 pretation is to be put upon the anomalies or exceptional cases 

 that may be met with, it is important to have some idea of the 

 antiquity of the existing groups, and of the rate at which the 

 forms of insect life have undergone modification. The geo- 

 logical record, if imperfect in the case of the higher animals, 

 is fragmentary in the extreme as regards indications of former 

 insect life; yet the positive facts that it does disclose are of 

 great interest, and have an important bearing on our subject. 

 These facts and the conclusions they lead to have been discussed 

 in our first volume (p. 166), and they must be carefully weighed 

 in all cases of apparent conflict or incongruity between the dis- 

 tribution of insects and that of the higher animals. 



