110 
ANIMAL INTELLIGENCE. 
merely a rough and primitive way of communicating to 
fellow-workers the locality where their services are re- 
quired. He says : — 
Keeping these facts in mind, we have a key to the solution 
cf the press-gang operations which Lin cecum observed among 
the agricultural, and which have been fully described in other 
species. In the absence of any common head or directory, and 
of all executive officers, a change of location or any other con- 
certed movement must be carried forward by the willing co- 
operation of individuals. At first sight, the act of seizing and 
carrying off workers does not appear like an appeal to free-will. 
It is indeed coercive, so far as the first act goes. But, in point 
of fact, the coercion ceases the moment the captive is set down 
within the precincts of the new movement. The carrier-ant 
has depended upon securing her consent and co-operation by 
thus bringing her within the circle of activity for which her 
service is sought. As a rule, no doubt, the deported ant at 
once yields to the influence around her, and drops into the 
current of fresh enterprise, in which she moves with as entire 
freedom and as independently as any other worker. But she is 
apparently under no restraint, and if she so please, may return 
to her former haunts. 
Certain Ants of Africa . — Livingstone says of certain 
ants of Africa : — 
They have established themselves on the plain where water 
stands so long annually as to allow the lotus and other aqueous 
plants to come to maturity. When all the ant-horizon is sub- 
merged a foot deep, they manage to exist by ascending to little 
houses built of black tenaceous loam on stalks of grass, and 
placed higher than the line of inundation. This must have 
been the result of experience, for, if they had waited till the 
water actually invaded their terrestrial habitations, they would 
not have been able to procure materials foi* their aerial quarters, 
unless they dived down to the bottom for every mouthful of 
clay 1 
The Tree Ant of India and New South Wales . — These 
ants are remarkable from their habit of forming nests only 
in trees. According to Col. Sykes 9 account, the shape of 
the nest is more or less globular, and about ten inches in 
diameter. It is formed entirely of cow-dung, which the 
1 Missionary Travels, p. 328* 
