It is not all ants who do these things, nor do any do all of them, but where there are Aphides and also ants, it would seem to be the exception rather than the rule for the latter to neglect them. But Aphides, though the principal ant-cows of Europe, are not the only ones even there, whilst elsewhere various other species that have this honey-excreting property become their substitutes. “In the tropics,” says Belt, in his much-observing work, “their place is taken in a great measure by species of _coccidæ_ and genera of _Homoptera_, such as _Membracis_ and its allies. My pineapples were greatly subject to the attacks of a small, soft-bodied, brown coccus, that was always guarded by a little black stinging ant (_Solenopsis_). This ant took great care of the scale-insects, and attacked savagely any one interfering with them, as I often found to my cost when trying to clear my pines by being stung severely by them. Not content with watching over their cattle, the ants brought up grains of damp earth, and built domed galleries over them, in which, under the vigilant guard of their savage little attendants, the scale insects must, I think, have been secure from the attacks of all enemies.”[47] And again, the same naturalist tells us, “The pawpaw trees growing in my garden were infested by a small brown species of _Membracis_—one of the leaf-hoppers that laid its eggs in a cottony nest on the under part of the leaves. The hopper would stand covering the nest until the young were hatched. These were little soft-bodied, dark-coloured insects, looking like Aphides, but more robust, and with the hind segments turned up. From the end of these the little larvæ exuded drops of honey, and were assiduously attended by small ants belonging to two species of the genus _Pheidole_. A third ant—a species of _Hypoclinea_—which I have mentioned before as a cowardly species, whenever it found any young hoppers unattended, would relieve them of their honey, but would scamper away on the approach of any of the _Pheidole_. The latter do not sting, but they attack and bite the hand if the young hoppers are interfered with.”[47] The latter “are, when young, so soft-bodied and sluggish in their movements, and there are so many enemies ready to prey upon them, that I imagine that in the tropics many species would be exterminated if it were not for the protection of the ants.”[47]