188 THE THEOKY OF EVOLUTION 



meet with other roots, can now nourish itself but very 

 imperfectly. 



(2) Adaptive phenomena in Symbiotics (Ant guests 

 and Termite guests], or Myrmecophils and 

 Termitophils. 1 



' Ant guests and Termite guests ' or Myrmecophils 

 and Termitophils are those Arthropods, especially 

 insects and mostly beetles, which regularly hve in 

 association with Ants or Termites. Already (in 1894) 

 they numbered 1419 species ; 3 at present they may be 

 roundly estimated at 3000, in consequence of the subse- 

 quent great advance of this zoological branch of research. 

 We find in these animals adaptations of the most diverse 

 character in the bodily form to the myrmecophil or 

 termitophil mode of life. In the first place we find 

 curious beetles provided with yellow or red bunches 

 of hair on the most diverse parts of their bodies, or 

 with other ' exudatory organs ' which are eagerly 

 licked and cared for by the Ants or Termites, and the 

 beetles are often fed from their mouths ; these constitute 

 the so-called Symphil type or ' true guest type/ Others 

 of these guests show, in bodily form and colour, often 

 also in the form of the antennae, a striking resemblance 



1 It appeared to us better, by one thoroughly treated instance, to make 

 the chain of evidence clear to the reader, rather than to give a purview 

 of the whole of the observation material. The study of the Ant and 

 Termite guests belongs to the special domain of P. E. Wasmann, who has 

 occupied himself with the study for decades. The following remarks 

 are entirely from his pen and were written specially for this work. 



2 Wasmann : Kritisches Verzeichnis der myrmekophilen und termito- 

 philen Arthropoden. 



