ANT AND TEEMITE GUESTS 



195 



as a Diptera but as a new genus, of the Rhynchotae 

 which, however, form quite another order of insects. 



We must also mention here the myrmecophil wing- 

 less Diptera genera Aenigmatias and Oniscomyia, which 

 resemble rather a Blattid of the order of Orthoptera 

 or a small Isopod than a fly and this again through 

 the adaptation of characters to the myrmecophil mode 

 of life to which they owe their systematic peculiarities. 

 Also among the other Diptera we meet with many 

 myrmecophil genera, such 

 as Microdon, Ephippomyia, 

 Harpagomyia, etc. 



FIG. 37. PHYSOGASTRE IMAGO OF 

 Termitoxenia Assmuihi. 



(After Wasmann.) 



We come now to the under- 

 lying principle of the above 

 examples. It is based on the 

 evidence of palaeontology, 

 comparative morphology and 

 biology, and the individual 

 evolutionary history. 



(a) Palaeontology shows us that the systematic orders 

 of the Arthropods, to which the Ant guests and Termite 

 guests belong, appeared very much earlier in the world's 

 history than the Ants and Termites themselves. Thus, 

 so we conclude, the guests belonging to those older 

 Arthropod orders could not be absolutely ' created ' 

 for their later-coming hosts, but have only later been 

 evolved by way of natural evolution out of originally 

 independent living forms by adaptation to the 

 myrmecophil or termitophil mode of life into the 



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