1 64 WILLIAM MORTON WHEELER. 



or vegetation. The small size of the eyes in the worker as com- 

 pared with other species of Megalomyrmex indicates that this 

 hypogaeic mode of life is beginning to affect the visual organs. 

 Other obvious adaptive characters are the dentition of the 

 mandibles, which is well suited to cropping the fungus hyphse, 

 and the investment of long, golden yellow hairs, which suggest a 

 trichomal function like the golden tufts of many symphilic 

 myrmecophiles. 



Some experiments were conducted in mingling the personnel 

 from different Sericomyrmex and Cepobroticus colonies. The 

 former were so gentle and tolerant that when workers and queens 

 belonging to different colonies were placed in the same Petri dish 

 little animosity and that of very short duration was exhibited. 

 Similarly, when inquilines from an alien colony were introduced, 

 they were adopted at once without hostility, but the members of 

 different colonies of the inquilines were much more hostile to one 

 another. Frequently workers or queens would be dragged about 

 for days and eventually mutilated or even killed by workers of 

 their own species. This behavior was, perhaps, to be expected 

 from what is known of the mutual animosity of parasites of the 

 same species when confined with a single host. 



The foregoing observations make it seem probable that the 

 Sericomyrmex- Cepobroticus colonies are not established by a con- 

 sociation of fecundated queens of the two species immediately 

 after their nuptial flight, but that the Cepobroticus queen enters a 

 well-established Sericomyrmex nest in which the fungus garden is 

 already large and flourishing and being cultivated by a lot of 

 workers. The development of the garden by the recently 

 fecundated Sericomyrmex queen, as already suggested, evidently 

 takes place in the same manner as in A tta, Acromyrmex, Mcellerius, 

 Apterostigma and other Attini, and is such a slow and delicate 

 operation that the presence of a fungus-devouring inquiline at the 

 inception of colony formation would, to say the least, seriously 

 interfere with the welfare of both queens. On the other hand, the 

 intrusion of the Cepobroticus queen at a later stage, when the 

 garden is well established, would not seriously affect the life and 

 development of both colonies, especially as the inquiline is by no 

 means a very fecund ant. This is shown by the small size of her 



