172 TEANSACTIONS OF THE 



little chamber, which contains the reproductive organs. The narrow 

 part of the tube is beset with long stiff hairs, which point down like 

 the wires of a mouse-trap, and give ready access to insects, but pre- 

 vents their escape. Soon after this the hairs shrivel up and allow 

 the insect to escape. The insect then flies to another flower with the 

 pollen masses attached to its body, passes down the narrow tube as 

 before, deposits some pollen on the stigma, and fertilises the plant. 

 In order to prevent the same flower being visited twice, it is seen 

 that after the pollen is shed the flower that was previously erect 

 falls over and withers. In order to prevent large insects from 

 alighting on the flower, the trumpet-shaped end is provided with 

 long stiff hairs pointing out in all directions. In Salvia pratensis, 

 the anthers, as they shed their pollen, shrivel up ; and, on the other 

 hand, the pistil increases in length, till it comes to block up 

 the entrance to the corolla. The stamens here are reduced 

 to two, and of those two only one half develops pollen. The 

 barren half is widely separated from the fertile one by the 

 connective. This connective rotates upon its axis upon the filament 

 of the stamen. The lower lip of the corolla forms a good landing- 

 place for insects, and the barren parts of the anthers block up the 

 entrance to the corolla tube. To explain the fertilisation here, 

 suppose an insect were to visit the flower in the male stage, it will, 

 in pushing its head down the corolla tube, come in contact with 

 the barren part of the anther, which, revolving upon its axis, will 

 get pushed into the back part of the corolla, and the fertile half will 

 at the same time be brought down upon the back of the insect, and 

 brush its pollen on to the back of the insect. Now, suppose that 

 the insect were to visit a flower in the female stage, where the pistil 

 had elongated and curved round so as to block up the entrance to 

 the corolla tube, the first thing that it would come in contact with 

 would be the elongated pistil, and as its back and sides were dusted 

 over with pollen, some of that pollen would be sure to be dusted on 

 to the stigma, and so the plant would be fertilised. This last 

 example is certainly the most wonderful arrangement for the pre- 

 vention of self-fertilisation that is to be found in the vegetable 

 kingdom. The paper was illustrated throughout by carefully- 

 executed diagrams. 



