Page:The Zoologist, 4th series, vol 3 (1899).djvu/481

Rh of fish, frogs, and tadpoles, some of which may probably be attracted within reach by mistaking the appendages on the neck for plants or animals on which they feed." "There occurs at the Cape of Good Hope a harmless egg-eating Snake (Dasypeltis scabra), which flattens its head, coils as if for a spring, hisses, and darts forward as though about to strike in a way that closely resembles the characteristic mode of the Berg-Adder (Vipera atropos), of which it is mimetic. It is really quite harmless, subsisting on eggs, the shells of which are broken in the throat by the enamel-tipped processes of the vertebræ, which project into the gullet, and form the so-called gular teeth; but its resemblance both in form and behaviour to a venomous Snake presumably affords it protection from enemies."

When we approach the annals of entomology, we find this explanatory idea permeating the whole subject. To suggest a new instance of mimicry is considered more desirable by many than to describe a new species; while the advocates or followers of both procedures do not always seem to practise mutual admiration. The observations are not all modern. The old Swedish traveller in South Africa, Dr. Sparrmann, who first discovered (1775) the curious hemipteron, Phyllomorpha paradoxa, was impressed by its mimetic resemblance to a leaf. "At noontide I sought for shelter among the branches of a shrub from the intolerable heat of the sun. Though the air was now extremely still and calm, so as hardly to have shaken an aspen leaf, yet I thought I saw a little withered, pale, crumpled leaf, eaten as it were by caterpillars, flittering from the tree. This appeared to me so very extraordinary that I thought it worth my while suddenly to quit my verdant bower in order to contemplate it; and I could scarcely believe my eyes when I saw a live insect, in shape and colour resembling the fragment of a withered leaf, with the edges turned up and eaten away, as it were by caterpillars, and at the same time all beset with prickles. Nature, by this peculiar form, has certainly extremely well defended and concealed, as it were in a mask, this insect from birds and its other