Page:Transactions of the Linnean Society of London, Volume 12.djvu/73

Rh suitable to its purpose; then hanging its posterior extremity over the margin, it ejected on the internal surface of the tube a larva with a black head, which immediately proceeded downwards by a brisk vermicular motion. This viviparous musca was more than double the size of the common house-fly, had a reddish head, and the body hairy, and streaked grayish. I had often noticed it before among the S. aduncæ, but could never ascertain its object; the hoods probably obstructing my view.

That insects may be found in these tubes which were not allured by the bait, I have well ascertained. At the time that I discovered the origin of the larvæ, I observed a beetle (Scarabæus carnifex, a herd being near) in its flight strike against the erect appendage of the S. flava and fall into the tube. In the leaves of the S.adunca, growing on the margin of a large pool, I once observed the fragments of a large Gryllus and several Gyrini. These and similar appearances have led me to suspect that our large Nepa, an extremely voracious insect, may occasionally use these tubes as storehouses. The hooked feet of this last insect would doubtless enable it to ascend against the inverted pubescence.

What purposes beneficial to the growth of these plants may be effected by the putrid masses of insects, I have never ascertained; but I learn from a hint given in the article Dionæa, in Rees's Cyclopædia, that it has been discovered that the air evolved is wholesome to the plants. I once entertained a suspicion that this air might be of such a deleterious nature as to cause the precipitation of the insects exposed to it, but I have long since relinquished it as entirely groundless.

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