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group of Camponotus workers busily engaged in perforating a 

 green thorn. It is probable, therefore, that the Camponotus 

 queens, after their nuptial flight, seek out the acacias and enter 

 their young thorns even when the trees are airead}' inhabited 

 by the Pseudomyrma, and that the Camponotus workers continue 

 this work side by side with the Pseudomyrmce , both species 

 competing for and taking possession of the thorns as fast as they 

 attain the proper size and maturity. It is certainly extra- 

 ordinary that C. planatus, which throughout tropical America 

 so constantly lives in hollow twigs, should be able in widely 

 separated localities to utilise the acacia thorns as perfectly and 

 in precisel}' the same manner as the regular Pseudom\Tmas. 

 That the Camponotus is, if anything, even more adroit in its use 

 of the extrafloral nectaries becomes apparent when one follows 

 the ant as it moves over the leaves, for it begins with the nectary 

 at the base of the petiole and carefully visits each in turn, whereas 

 the foraging Pseudomyrmas are much more desultory and less 

 businesslike. I have not seen the Camponotus collecting the 

 Beltian bodies, but I doubt not that they make quite as good use 

 of them as of the nectar. 



The behaviour of the two species of ants towards each other 

 is peculiar. They seem never to quarrel, and, if not too close 

 together, pass one another on the twigs and leaves with an air 

 of complete indifference. But when two of them happen to meet 

 squarely face to face, each starts back suddenly and, curiously 

 enough, the Pseudomyrma always recoils more vigorously than 

 the Camponotus. There is something ludicrous in this behaviour, 

 because both ants are of about the same bulk, and the Pseudo- 

 myrma is really the more powerful and possesses a formidable 

 sting, whereas the Camponotus is much less pugnacious and can 

 defend itself only with its rather feeble mandibles and formic acid 

 battery. But it smells rather strongly of formic acid, and I 

 believe that this produces the more decided reaction on the part 

 of the Pseudomyrma. 



Still another ant which I found repeatedly nesting in A. 

 cornígera bushes with Ps. fulvesccns in a pasture near Escuintla, 

 Guatemala, is a minute yellow Solenopsis, which seems not to 

 have been described. Its small colonies were not nesting in the 

 thorns, but in the old spindle-shaped flower-peduncles from which 



