HAE VESTING ANTS. 99 



harvest to the nest is very long, they make regular depots for 

 their provisions under large leaves, stones, or other suitable 

 places, and let certain workers have the duty of carrying them 

 from depot to depot. 



Biichner (loc. cit. p. 101) also makes the following 

 references to the statements of previous observers : 



The subterranean workers of this remarkable genus are very 

 clever. The Rev. H. Clark reports from Rio de Janeiro, that 

 the Sa-ubas have made a regular tunnel iinder the bed of the 

 river Parahyba, which is there as broad as the Thames at 

 London, in order to reach a storehouse which is on the opposite 

 bank. Bates tells us that close to the Magoary rice- mills, near 

 Para, the ants bored through the dam of a large reservoir, and 

 the water escaped before the mischief could be remedied. In 

 the Para Botanical Gardens an enterprising French gardener 

 did everything he could to drive the Sa-ubas away. He lit fires 

 at the chief entrances of their nests, and blew sulphur vapour 

 into their galleries by means of bellows. But how astonished 

 was Bates when he saw the vapour come out at no less a dis- 

 tance than seventy yards ! Such an extension have the sub- 

 terranean passages of the Sa-ubas. 



The recognition of the principle of the division of 

 labour, which is shown by the above observations, is further 

 corroborated by the following quotation from Belt : 



Between the old burrows and the new one Avas a steep 

 slope. Instead of descending this with their burdens, they cast 

 them down on the top of the slope, whence they rolled down to 

 the bottom, where another relay of labourers picked them up 

 and carried them to the new burrow. It was amusing to watch 

 the ants hurrying out with bundles of food, dropping them over 

 the slope, and rushing back immediately for more. 



The same thing has been observed, as already stated, 

 of the leaf-cutting ants those engaged in cutting fre- 

 quently throwing down the fragments of leaf which they 

 cut to the carriers below. The prevalence of this habit 

 among various species of ants therefore renders credible 

 the following statements of Vincent Gredler of Botzen 

 which are thus recorded in ' der Zool. Grart.,' xv. p. 434 : 



In Herr Gredler's monastery one of the monks had been 

 accustomed for some months to put food regularly on his window- 



