PERFECY SOCIETIES OF INSECTS. 89 
it. ‘Their sucker being inserted in the tender bark, is 
without intermission employed in absorbing the sap, 
which, after it has passed through the system, they keep 
continually discharging by these organs. When no ants 
attend them, by a certain jerk of the body, which takes - 
place at regular intervals, they ejaculate it to a distance: 
but when the ants are at hand, watching the moment 
when the aphides emit their fluid, they seize and suck it 
down immediately. This, however, is the least of their 
talents; for they absolutely possess the art of making 
them yield it at their pleasure; or, in other words, of 
milking them. On this occasion their antenne are their 
fingers; with these they pat the abdomen of the aphis 
on each side alternately, moving them very briskly; a 
little drop of fluid immediately appears, which the ant 
takes into its mouth, one species (Myrmica rubra) con- 
ducting it with its antennae, which are somewhat swelled 
at the end. When it has thus milked one, it proceeds 
to another, and so on, till being satiated it returns to 
the nest. 
Not only the aphides yield this repast to the ants, but 
also the Cocc7, with whom they have recourse to similar 
manceuvres, and with equal success; only in this case 
the movement of the antennae over their body may be 
compared to the thrill of the finger over the keys of a 
piano-forte. 
But you are not arrived at the most singular part of 
this history,—that ants make a property of these cows, 
for the possession of which they contend with great ear- 
nestness, and use every means to keep them to themselves. 
Sometimes they seem to claim a right to the aphides that 
inhabit the branches of a tree or the stalks of a plant; 
