7/2 Marvels of the Universe 
Out in the savannah there lives a little ant called Pseudomyrma, which, in addition to the business- 
like pair of jaws usual in ants, possesses a sting like a bee or wasp, whose effects on the human victim 
last for twenty-four hours. During the dry season this ant appears to live in the ground; but 
when the wet season arrives and the Acacia puts forth new shoots and unfolds new leaves, Pseudo- 
myrma will be found on the Acacia, and you cannot touch the plant without having a number of the 
ants swarming over your hands, biting and stinging at the same time. At the base of each pair of 
leaflets on the new leaves there is a little hollow, and at this time the plant pours into the hollow 
a sweet fluid much like the nectar with which most plants attract bees to their blossoms. The pur- 
pose is the same here, only it is ants instead of bees whose visits are sought. The ants love sweets 
and largely live upon them ; so numbers climb up the stems and twigs and run over the leaves in 
the search for these little saucers of sweet drink. Now, also, comes the great Sauba, intent on 
carrying home a load of leaves. But the alarm is 
spread among the much smaller stinging ants, and they 
immediately do battle with the Saubas and drive them 
off. There is no enemy the Sauba appears to dread so 
much as these little stingers. So does the Acacia 
benefit by its outlay in nectar. 
But it might be only a matter of chance that the 
stinging ants were in the way when the Saubas called ; 
how much better if the Acacia could induce its stinging 
friends to take up residence on its branches, and so_ be 
always on duty, patrolling the ways that lead to the 
leaves. The Acacia puts forth a new set of thorns, and 
fills them with a substance that will serve as ant food. 
By some mysterious means—possibly it is inherited 
the ants know this, and set to work to bore 
knowledge 
a hole in the upper part of one only of each pair of 
thorns. This aperture is large enough to serve as an 
entrance for the ants, and they soon clear out the in- 
terior. Strange to say, this treatment does not, as might 
be anticipated, stop the development of the thorn ; in- 
stead, it appears to stimulate it. Mr. Belt, to whom we 
are indebted for our knowledge of the relations between 
MOD [S. L. Bastin. the plant and the ants, reared the Bull’s-horn Acacia 
THE ACACIA ANT. 
The little stinging ant that lives in the hollowed 3 : 
Saney of the Aas al oot inartmson, Of Was Sxsccs Of ants amal Ino iOniMGl Wee Une wie 
(Much enlarged.) attended thorns did not attain their full size, but turned 
yellow and dried into small persistent prickles. Where the ants have access, however, they become 
larger at the base after they have been emptied. There is a natural division between the bases 
of a pair of thorns, but this the ants bore through, so that they have the run of both thorns with 
only one means of entrance and exit. In these thorns they construct nests and rear their young, 
and the moment any noisome leaf-fretting insect sets foot upon the plant the ants pour out of 
these receptacles and make an onslaught upon the intruder, who is stung and driven off if large, 
and, if small, is killed and eaten. 
Now the sweet fluid is only secreted by the leaves whilst they remain in a young and tender 
condition. Probably they are incapable of doing so when the leaves are fully developed ; but it is 
clear that this flow having ceased and the stuffing of the thorns having been consumed, the ants— 
supposing they stayed on the same Acacia—would have to make food-hunting forays, leaving the 
Acacia unprotected whilst they were away. The plant appears to have realized this difficulty, for 
from seed in the Nicaraguan forest, where there are none 
