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Page:Popular Science Monthly Volume 65.djvu/435

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SOME PLANTS WHICH ENTRAP INSECTS.

among the glands, pulls oil' such insects as it desires and either devours them on the spot or returns with them to its web. Not less wonderful is the fly which pollinates the flowers of the fly-bush, ft, too, is enabled, by possessing long legs, to walk in safety among the glandular hairs, and it takes pay for the service of having pollinated its flowers by puncturing the leaves and with its long proboscis sucking the juices of the plant.

So far as may be judged from rather limited observations the spider and the fly of the fly-bush are not found on any other plants. The spider has probably been attracted from other homes by the rich feeding ground, and, as for the fly, no one knows how complex may have been the history of its evolution. What more complicated relation between plant and animal can be imagined than this of the fly and fly-bush? A plant in need of nitrogenous food possesses effective traps for insects, from which this food is got. The plant is in need, too, of the services of insects for the pollination of its flowers. How can this plant, a death trap to insects, secure their service in pollination? Its large showy flowers attract many insects, but they find no honey to reward them for their visit, and if they linger about the plant their doom is sealed. The flower is not without honey, but the cells containing it are covered by a layer of ordinary cells, and when the long-legged fly makes its visits to the petals its proboscis is brought into use, the layer of cells is punctured, and. the honey obtained. Insured against harm the fly may then visit other parts of the plant, and here it will use its proboscis again on leaves or stems to plunder the plant of its sap.

How much akin these phenomena are, you will say, to bribery, deceit and the taking of unfair advantage. True, there is no altruism among the lower forms of life; the benefit of self and of posterity is the supreme good of the animal and of the plant, and. necessarily so by reason of the multitude of competitors and the keenness of the strife with them. Yet the great mass of plants live independently and, so to speak, honestly; overcoming obstacles and withstanding reverses, doing no more than energetic men in jostling their neighbors in the winning of a livelihood, and being no more than normal in providing that their own offspring should have a good start in the world rather than the offspring of their neighbors.