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Mar., 1910 EFFECT OF ENEMIES ON NESTING HABITS OF HONDURAS BIRDS 57 stream, from four to fifteen feet from the water. The greatest diameter is a little below the middle, and at this point the cavity is situated, which is entered by a small hole. The nest is composed of coarse fibrous material and covered over the outside with dry leaves, leaf stems, and large twigs, some of the last a foot or more in length. The whole'affair in almost every detail so closely resembles a small mass of debris left by a retreating flood, as to deceive the keenest enemy. Fur- thermore, the location assists greatly in the disguise, the nest appearing to be but one among thousands of such masses entangled in the vegetation overhanging the stream. Add to this the difficulty any reptile or mammal would experience in reaching it, even were its nature known, and we have a most striking example of protective adaptation. Todlroslrum cinereum and some other Tyrannidae make nests of precisely the same style as that of Onychorhynchus. That of T. cinereum is much less fre- quently built over a stream and is com- posed of finer material, often with so much cottony substance interwoven as to give it the appearance of a colony of "tent- caterpillars." (See Fig. 18.) The nests of two other small flycatchers, Todirostrum schislaceiceps and Oncosloma cinereigulare, are also suspended by the top from small branches and entered by a hole at the side, but are somewhat pear- shaped. They are built but two or three feet from the ground, and if they are as inconspicuous to the reptilian as to the human observer, they are comparatively safe. (See Fig. 19.) ]?hynchocyclus is a genus of small fly- catchers of obscure coloring and ordi- nary habits, noteworthy only for their curious nests, which are perhaps among the most remarkable examples of protective adaptation known. The nest of R. ciner- eiceps is built from ten to thirty feet above the ground, or water, as it frequently overhangs a stream. In shape it resembles an old shoe, or rather moccasin, sus- Fig. 19. ?Es'? OF ??Iil? SLA??I?-III?ADI?D TODY FLY-CATCttER, TOI)IRO,S'TRU)?I' pendeal by the top with the entrance at the toe, and a narrow passage leading over the instep to the heel, where the main cavity is sithated. It is composed of some kind of aerial r6ots--long, fine black fibers resembling horse hair. It usually hangs from a long, slender branch of one of those myrmecophilous acacias, whose stout double spines are hollow and inhabited by ants. The thorns are very nu- merous and the ants are extremely irritable and armed with formidable stings, equal in effectiveness to that of the bumble bee. The thorns alone would make the ascent of the tree by an animal of any size very difficult, but the presence of the ants renders it absolutely impossible. But this is not all. A species of hornet frequently makes its nest, a large conical or oval structure, in the same tree, and