is only those moths and butterflies which, forcing their long proboscis down the honey-laden tube, must accomplish cross-fertilization. But failing this, the plant is more or less at the mercy of hosts of insect triflers, mere pollen eaters, who may or may not insure cross-fertilization, but in any case provide for self-fertilization. Another use which certain plants make of honey, besides acting as a lure of insects, is found in the common lilac. The flower in this has considerable honey at the bottom of the tube, which can only be reached by insects with a proboscis sufficiently long to reach it. The lilac has only two stamens inserted near the top of the tube, the passage to which they very nearly obstruct. The stigma is hidden in the tube, and it matures simultaneously with the ripening of the pollen. As the insect inserts its proboscis between the stamens no pollen clings to it due to the character of the pollen grains. But as the proboscis is withdrawn from the tube its lower end is covered with honey to which pollen sticks. If a needle is inserted between the stamens and pushed only far enough to be still clear of the honey, no pollen will be found on it when withdrawn, but if pushed all the way down, its honey-coated point will catch considerable pollen. In the lilac, if insect visitors do not accomplish the work of cross-fertilization, the flower is self-fertilized ultimately by the protruding of the stigma far enough out of the tube to catch some of the remaining pollen grains. It is perhaps useless to multiply instances of flowers which by various devices secure the cooperation of insects in getting pollen from a foreign source. To recapitulate some of those devices it is necessary only to recall what some flowers have done to force cross-fertilization. The heated chamber of the magnolia, the cruelty of the prison cell in Dutchman’s-pipe, the blow from the stamen of the barberry, the faithful rotation of the ten stamens of the gas plant, the explosive flower in some members of the pea family, the lure of honey and seductive odor of the Italian honeysuckle, the mathematical complexity of the loosestrife--these and hundreds of others all point to the necessity of cross-fertilization and a means to produce it almost beyond belief. There is the best of evidence that not only flowers but insects themselves have been modified in this great work, and that for every flower needing cross-fertilization some agency has been developed to secure it. Insects, beyond all other animal life, do this work, but it is accomplished by humming birds often, and in one plant even by a snail.