I AM glad to be able to confirm, to-some extent, from observation, Mr. Bennett's theory of the fertilisation of the Pansy, given in NATURE, vol. viii. p. 49. I watched a considerable number of specimens of Viola tricolor on a grassy hill-top where the smaller insects were very numerous and busy, and twice saw them entered by a minute fly. In the first case the insect was dusty with pollen when it arrived. It settled on the lower petal and walked up one of the black lines to the gap in the ring of anthers, through which it entered with some difficulty—leaving some of the foreign pollen on the stigma as it passed. When it came out it had still more pollen on it than when it went in, and again in passing the stigma it left some on it. It paused a moment on the lower petal to clean itself and left a little ball of pollen on the hairs on one side of the stigma. In the second case, the insect alighted first on one of the upper unmasked petals, turned round and round as though seeking the guiding lines, and flew off to the lower petal, where, without hesitation, it followed the guiding lines as the other had done. After it lied passed the stigma there was no pollen visible on its surface; but after it had come out, almost the whole of the lower half was covered. In each case the passage through the ring of anthers seemed rather a struggle. There were many bees about, but I did not see any of them visit the Violae, although they were almost the only flower near.