198 THE THEORY OF EVOLUTION 



' created specially/ The futility of this assumption 

 is obvious. 



(b) The second source of evidence for the underlying 

 principle is to be derived from the facts of comparative 

 morphology and biology, and specially from the examples 

 of recent formation of species which we have derived 

 from a series of works on the Ant guests and Termite 

 guests. We find, namely, still in the present time 

 clear traces of a formation of ' new species ' in this 



FIG. 38. Ecitophya simulans Wasm. 

 (S. Catharina, Brazil ; mag. 5 diam.) 



domain of research. Two of such examples must here 

 suffice to be mentioned. 



Within the hemipterous genus of Dinarda we find 

 a series of bicoloured (red and black) ' forms ' which 

 live with various species of the Ant genus Formica 

 in Europe and Asia and are so adapted to them that 

 they regulate themselves as regards their size and 

 coloration according to those of their particular host 

 Ant species. Two of these forms Dinarda dentata 

 and Markeli which live with Formica sanguined and 

 Formica rufa respectively, cannot already be dis- 

 criminated from so-called ' good species/ and occur 

 also throughout the whole domain occupied by their 



