BEHAVIOR OF SPIDERS AND OTHER INSECTS 393 



changed several times and between these changes there were 

 migrations and dispersals, just as there is to-day. So that 

 to-day each continent has insects which by their structure and 

 origin are isolated from other insects around them and find their 

 relations only in insects of distant countries." In western North 

 Carolina there is a species of Panorpodes, a genus whose only 

 other habitat is Oregon and Japan. In the southern Appa- 

 lachians there is a spider (Hypochilus) which occurs elsewhere 

 only in Colorado and which has a closely related genus in North 

 China and New Zealand. In eastern S. America there is a hand- 

 some genus of ant-lions (Dimares) unlike anything else in S. 

 America, but is so closely related to species of a genus found in 

 Africa, Arabia and Ceylon that one loathes to separate them. 

 Evidently the types of insect fauna do not agree with those of 

 mammalian and avian fauna. There are three major types of 

 insect fauna; (1) the microtypal, including insects of Europe, 

 N. America, N. Asia, a considerable element of Andean America, 

 many species in India, Insulidae and New Zealand, a distinct 

 representation in Australia and a poor development in Africa; 

 (2) the African or Gonwandan, with its present home in Africa, 

 but strongly developed in Australia and almost as well developed 

 in Insulidae and Ceylon, plainly present in India and noticeable 

 in the Americas; (3) the Brazilian, with its center in Brazil. 

 The third is a recent development; the other two are of ancient 

 origin. 



Banks analyzes the present insect fauna of the U. S. A. into 

 the following elements. (1) Genera which are the relicts of a 

 very ancient fauna which existed when the land masses were 

 of a different formation from now. These are isolated in our 

 fauna and are mostly examples of discontinuous distribution. 



(2) Genera representing relicts of an ancient invasion from S. 

 America possibly through the West Indies, after S. America 

 had been connected with Africa or a Pacific continent. These 

 genera are isolated systematically in our fauna; they are forms 

 that look out of place among our insects and are usually repre- 

 sented in northern Europe neither by recent forms nor by fossils. 



(3) Genera originating in this country from an insect fauna of 

 which the elements " 1 " and " 2 " are relicts. These are con- 

 fined to the United States and their affinities are with S. American 

 or Asian insects rather than with those of Europe. " I consider 



