Page:The Zoologist, 4th series, vol 3 (1899).djvu/380

352 small bush, and, though I have searched carefully, have not been able to find him; the only way is to remain quite quiet till he again begins his song."

The aquatic larvae known as the Small "Bloodworm" (Tubifex rivulorum) is another instance of an animal whose colouration is a lure to its destruction, and whose fecundity can alone enable it to survive. The angler knows how readily a dish of Gudgeon can be procured with this bait; whilst other well-known ground fishes, such as the Loach (Cobitis barbatula), and the Miller's-thumb (Cottus gobio) also greedily attack it. These small worms live in great numbers in the mud at the bottom of streams, and, as Mr. Beddard has observed, as "the head-end is fixed in the mud, while the tail waves about freely in the water, these worms form exceedingly conspicuous red patches, which must attract ground-feeding fish."

It is often urged that few observers have seen butterflies attacked by birds, and that therefore their protective and warning colours are little needed against these as foes. Similar remarks have been made with reference to other animals. Thus Mr. Andrew Lang writes:—"On the Dee, Salmon sometimes rise to March Browns, and take the artificial March Brown tied rather large on these occasions. I have never seen a Salmon take a natural fly, any more than I have seen a phantasm of the dead"; yet he adds he "can believe on good evidence that Salmon do take natural flies." Undoubted trustworthy accounts do exist also as to avian attacks on Lepidoptera, and the writer has witnessed not a few, though the occurrence is somewhat uncommon. Eimer once came across a large concourse of white and blue butterflies on a high plateau of the Swabian Alp: "On my approach a number of birds (Stonechats) flew from the spot, and when I came up I found a number of maimed butterflies lying fluttering on the ground; pieces had been bitten from the wings of most of them—indeed the wings were often torn to pieces