. Entomology : with special reference to its biological and economic aspects. B, ovipositor.—After Riley. Fig-ures 256-258 are republished from the ThirdReport of the Missouri Botanical Garden, bypermission. INSECTS IN RELATION TO PLANTS 265 the pistil and actually thrusts pollen into the stigmatic tube andpushes it in firmly. The o\ules developinto seeds, some of which are consumedby the larva;, though plenty are left toperpetuate the plant itself. Three speciesof Promiha are known, each restrictedto particular species of Yucca. Rileysays that Yucca never produces seedwhere Prouuba does not o
. Entomology : with special reference to its biological and economic aspects. B, ovipositor.—After Riley. Fig-ures 256-258 are republished from the ThirdReport of the Missouri Botanical Garden, bypermission. INSECTS IN RELATION TO PLANTS 265 the pistil and actually thrusts pollen into the stigmatic tube andpushes it in firmly. The o\ules developinto seeds, some of which are consumedby the larva;, though plenty are left toperpetuate the plant itself. Three speciesof Promiha are known, each restrictedto particular species of Yucca. Rileysays that Yucca never produces seedwhere Prouuba does not occur or whereshe is excluded artificially, and thatartificial pollination is rarely so success-ful as the normal method. Why does the insect do this? The lit-tle nectar secreted at the base of the pistilappears to be of no consecjuence, at pres-ent, and the stigmatic fluid is not necta-rian; indeed, the tongue of Prouuba, usedin clinging to the stamen, seems to havelost partially or entirely its sucking power,and the alimentarv canal is resrarded as functionless. Ordina-. Pronuba yticcasetla, fe-male, gathering pollenfrom anthers of Fig. 2--,S.
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