WERNER MARCHAND 189 



siderable distance from water and probably a greater number than is 

 apparent from this table, because terrestrial larvae will be found 

 much more rarely being less accessible and spread over wider areas. 

 Since the genus Tabanus is on the whole phylogenetically the 

 younger, in comparison with Chrysops, it would appear that in some 

 species of this genus the larvae have become secondarily terrestrial, a 

 possibility which is of importance for the understanding of the group 

 as a whole. This may also apply to Hcematopota, a genus absent 

 in Australia and apparently of more recent origin — while retaining a 

 rather primitive wing-pattern — showing aquatic tendencies in the 

 oviposition of some species, yet in its common and widely spread 

 species, HcBmatopota pluvialis, completely terrestrial in the larval and 

 pupal stages. 



Practically nothing is known, with the exception of the few in- 

 stances listed, of the early stages of the numerous remaining genera 

 of the family Tabanidas other than Chrysops and Tabanus proper, 

 and here is a splendid opportunity especially for workers in tropical 

 countries. 



In regard to continents, the data in our possession are distributed 

 as follows: 



(Two identical with European; viz., African 

 species.) 



It is seen that Africa ranges highest, and concerning this particular 

 subject, has ceased to be a "dark continent," as compared with 

 North America or Europe. 



