Page:The Zoologist, 4th series, vol 3 (1899).djvu/384

356 second, that of probabilities; and the third, that of dreams," By the term "Demonstrable" is implied all those instances where protection, absolute or partial, has been or can be demonstrated by experiment or actual observation. "Suggested or Probable" should, however, be applied to those examples where, because we see similarity of structure, markings, or colour, we assume—and probably often correctly—that protection is involved, though no direct knowledge of the same is obtainable. As an illustration, we know that certain Diptera, Eristalis spp., resemble Bees, and we conclude that this simulation has arisen by evolutionary means for protective purposes. It must nevertheless be remembered that the Bee itself is not absolutely protected by its sting, and does not possess a corresponding immunity from the attacks of all its enemies. Mr. Woodford, on Peel Island, Moreton Bay, observed Bees of the genus Bombus caught and devoured by Spiders. Prof. Lloyd Morgan's experiments, however, demonstrate protection at least from birds:—"To another group of chicks I just gave Hive Bees, which were seized, but soon let alone, and then the Droneflies (Eristalis), which so closely mimic the Hive Bee. They were left untouched. Their resemblance to the Bees was protective." Frank Buckland relates:—"A gentleman in Oxfordshire had a hive of Bees in the cavity of a wall. A common Toad which had taken up its residence in a hole close by was observed to walk forth and place himself at the mouth of the hive, and so catch the Bees in their coming from and returning to the hive with much dexterity and activity. After witnessing the Toad at work for some time, and feeling convinced that, if his depredations were suffered, he would eventually destroy the whole hive, the owner of the Bees killed the robber, and on inspecting his stomach it was found full to repletion of dead Bees."