Lyonnet was unable to discover the use of the so-called mast, and it remains a mystery to this day, so that the imaginary philosopher might have a better chance here, were it not his _métier_ to be put to confusion. It is hollow, and as the cocoon contains air, with which the beetle supplies it—just as the water-spider does her diving-bell—Miger, whose observations were made in 1807, some fifty years after those of Lyonnet, supposed it might serve as the channel of entry. But, although hollow, it has no orifice, but is closed at the end, and this does not seem to accord with the above view. Mr. G. A. Laker, a modern observer, does not think that the spike can serve as a balance to the cocoon, since this is usually attached to some weed, or other supporting substance. He, however, cut the spike off two of the cocoons, and the eggs in both of these remained unhatched. Moreover, these cocoons subsequently sank, whereas in their normal state they “are so constructed that when floating loose the spike retains its proper position, and even if the cocoon be held so that the spike is parallel with the water and then suddenly released, it immediately rights itself.”[144] The balance theory, therefore, certainly seems to have something in its favour. Lyonnet’s own conjecture was that the mast, as he calls it—a designation against which Miger protests—might merely represent the waste silk which the beetle felt impelled to get rid of. The time taken by the beetle in making the whole cocoon is about five hours, whilst the mast, spike, or turned-up point, as Miger severely calls it, takes it half an hour. It is curious that whereas Lyonnet’s cocoons held “about a hundred” eggs, Mr. Laker gives the number as “usually between fifty and sixty.”[144]