The Malay archipelago : the land of the orang-utan ... - Wallace Online

XXIV.] BATCHIAK 265usual and exceptional necessity. The bird does not ordinarilyrequire great powers of flight, since it lives in the forest, feedson fallen fruits, and roosts in low trees like other groundpigeons. Tlie majority of the individuals, therefore, can nevermake full use of their enormously powerful wings, till the exceptionalcase occurs of an individual being blown out to sea,or driven to emigrate by the incursion of some carnivorousanimal, or the pressure of scarcity of food. A modificationexactly opposite to that which produced the wingless birds (theApteryx, Cassowary, and Dodo), appears to have liere takenplace ;and it is curious that in both cases an insular habitatshould have been the moving cause. The explanation is probablythe same as that applied by Mr. Darwin to the case of theMadeira beetles, many of which are wingless, while some of thewinged ones liavethe wings better developed than the samespecies on the continent. It was advantageous to these insectseither never to fly at all, and thus not run the risk of beingblown out to sea, or to fly so well as to be able either to returnto land, or to migrate safely to the continent. Bad flying wasworse than not flying at alL So, while in such islands as°NewZealand and Mauritius, far from all land, it was safer for aground-feeding bird not to fly at all, and the sliort-winged individualscontinually surviving, prepared tlie way for a winglessgroup of birds ;in a vast Archipelago thickly strewn withislands and islets it was advantageous to be able occasionally tomigrate, and thus the long and strong-winged varieties maintainedtheir existence longest, and ultimately supplanted allothers, and spread the race over the whole Archipelago.Besides this pigeon, the only new bird I obtained during thetrip was a rare goat-sucker (Batrachostomus crinifrons), theonly species of the genus yet found in the Moluccas. Amongmy insects the best were the rare Pieris aruna, of a ricli chromeyellow colour, with a black border and remarkable whiteantenna? —perhaps the very finest butterfly of the genus ; and alarge black wasp-like insect, with immense jaws like a stagbeetle,which has been named Megachile pluto by Mr. F. Smith.I collected about a hundred species of beetles quite new to me*but mostly very minute, and also many rare and handsome oneswhich I had already found in Batchian. On the whole I wastolerably satisfied with my seventeen days' excursion, whicliwas a very agreeable one, and enabled me to see a good deal ofthe island. I had hired a roomy boat, and brought with me asmall table and my rattan chair. These were great comfortsas, wherever there was a roof, I could immediately instal myself,and work and eat at ease. When I could not find accommodationon shore I slept in the boat, which was always drawnup on the beach if we stayed for a few days at one spot.On my return to Batchian I packed up my collections andprepared for my return to Ternate. When I first came I hadsent back my boat by the pilot, with two or three other men