522 



Vol. XLIII 



Let us take, for example, the case of Carabus, a genus 

 of running beetles so familiar to North American ento- 

 mologists. They are by no means easily transported to 

 great distances by gales and hurricanes as Dr. Wallace 

 avers, for the simple reason that these beetles can not fly. 

 Their wing cases are permanently soldered together, and 

 being generally found under clods of earth or beneath 

 stones, the action of winds can have no appreciable influ- 

 ence on their dispersion. They are typical inhabitants of 

 the northern hemisphere, being abundant in Europe, 

 northern Asia and North America. A single species 

 occurs in western Mexico. No Carabus has ever been 

 taken in Central America or in the northern or middle 

 states of South America. Yet in Chile and spreading 

 into Argentina, no less than eleven species have been 

 observed. For a distance of about fifty degrees of lati- 

 tude the running beetles of the genus Carabus are quite 

 absent and then reappear further south in numbers. 

 Those entomologists, like Mr. Born, 29 who have made a 

 special study of the Carabidae, consider them eminently 

 fitted for the purpose of demonstrating former changes of 

 land and water. 



Of the northern genera of butterflies Colias, Lycaena 

 and Argynnis, which occur in Chile, the presumption, at 



dental or occasional means of dispersal, such as those sug- 

 gested by Dr. Wallace. Yet the case of the ant Lasius, a 

 northern genus, which reappears in Chile, is more difficult 

 of explanation on such an hypothesis. 



We can not say of anv of these invertebrates that they 

 are confined to western M,xi,u in Xurtl. America, though 

 this appears to be the most southerlv point on the north- 

 ern continent where thev occur. On the other hand the 

 primitive earthworm Kerria is only known from Lower 

 California and from the southern part of South America 

 in Chile and Argentina. From the latter country it seems 

 to have spread into Paraguay and southern Brazil. 



