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subject with an ever-increasing literature. 

 Every kind of flower has its own particu- 

 lar way of solving the problem, so that the 

 subject will never be completed until all 

 flowers have been questioned and their 

 answers obtained. 



Any account, however brief, should not 

 omit mention of the orchids, which in the 

 matter of insect-pollination have reached 

 the highest degree of organization. So 

 detailed are their adaptations that each 

 kind of flower is adapted to a particular 

 kind of insect. The accounts given of the 

 various ways in which orchids attract 

 insects and secure pollination really sur- 

 pass belief, until one has actually ob- 

 served some of the plants and their in- 

 sects at work. Any greenhouse furnishes 

 abundant examples of orchids, and our 

 illustration represents one of the most 

 common of our native orchids, the ordi- 

 nary yellow Ladyslipper. In most orchid 

 flowers there is a long tubular spur, at the 

 bottom of which the nectar is found, 

 which is to be reached by long probosces, 

 such as can be found only in moths and 

 butterflies. In Ladyslippers, however, 

 there is a dififerent arrangement. The 

 flowers have a conspicuous pouch in 

 which the nectar is secreted, and a flap 

 overhangs the opening of the pouch. Be- 

 hind the flap are the two pollen masses, 

 between which is the stigmatic surface. 

 A bee crowds itself away into the pouch 

 and becomes imprisoned, and may fre- 

 quently be found buzzing about uneasily. 

 The nectar is in the bottom of the pouch, 

 and after feeding the bee moves toward 

 the opening overhung by the flap, and 

 rubs itself against the stigma and then 

 against the anthers, receiving the pollen 

 on its back. A visit to another flower will 

 result in rubbing some of the pollen upon 



the stigma, and in receiving more pollen 

 for another flower. 



One of the most remarkable cases of in- 

 sect-pollination is that shown by the ordi- 

 nary Yucca, which is pollinated by a small 

 moth, the plant and the moth being very 

 dependent upon one another. The flow- 

 ers of Yucca occur in very large prom- 

 inent clusters, and hang like bells. In' 

 each bell-shaped flower there are six 

 hanging stamens, and a central ovary 

 ribbed lengthwise like a melon. At the 

 tip of the ovary is a funnel-shaped open- 

 ing, which is the stigma. During the day 

 the moth hides quietly in the recesses of 

 the flower, but at dusk she becomes very 

 active. She travels down the stamens, 

 and, resting on the open anthers, scrapes 

 out the somewhat sticky pollen with her 

 front legs. Holding the little mass of 

 pollen she runs up on the ovary, stands 

 astride of one of the furrows, pierces 

 through the wall with her ovipositor, and 

 deposits an egg in an ovule. After depos- 

 iting several eggs, she runs to the apex 

 of the ovary and begins to crowd the mass 

 of pollen she has collected into the funnel- 

 like stigma. These actions are repeated 

 several times, until many eggs are depos- 

 ited and repeated pollination has beeni 

 efTected. As a result of all this, the flower- 

 is pollinated and seeds are formed, which) 

 develop abundant nourishment for the 

 moth larvae, whose eggs had been laid; 

 in the ovule. Just how the insect learned! 

 that this behavior on her part would se- 

 cure food for her young is hard tC' 

 imagine. 



In studying any flower there are three 

 questions that should be asked: (i) How 

 does it hinder self-pollination ? ; (2) How 

 does it secure cross-pollination ? ; (3) How 

 does it discourage the visits of unsuitable 

 insects ? John Merle Coulter.. 



