As we have mentioned, the jaws open vertically; but the mandibles and maxillæ work horizontally. They are thus enabled to seize and tightly hold any object they can grasp. The mandibles of the drone and the queen have two notches or teeth. Those of workers are not thus furnished, probably because, for shaping and smoothing the cells, an unbroken edge is much more convenient than a notched one. These organs are, however, very strong, and enable their possessor to grasp enemies, drones or queens; to nibble hard kinds of food; to break away pieces of damaged comb; and to mould wax for building purposes. In the last of these operations they are, doubtless, aided by the shear-like maxillæ. CHAPTER XII. HEARING, TASTE, AND SMELLING. Hearing--Sir John Lubbock's Experiments--Sounds uttered by Queen--Effects produced by them--Smell-Organs--Purposes--Liking for, and Antipathy to, certain Effluvia--Discovery by Bees of Nectar and Honey With regard to the sense of hearing, Sir John Lubbock says: "The result of my experiments on the hearing of bees has surprised me very much. It is generally considered that, to a certain extent, the emotions of bees are expressed by the sounds they make, which seems to imply that they possess the power of hearing. I do not by any means intend to deny that this is the case. Nevertheless, I never found them take any notice of any noise which I made, even when it was close to them. I tried one of my bees with a violin. I made all the noise I could, but, to my surprise, she took no notice. I could not even see a twitch of the antennæ. The next day I tried the same with another bee, but could not see the slightest sign that she was conscious of the noise. On August 31st I repeated the experiment with another bee, with the same result. On September 12th and 13th I tried several bees with a dog-whistle and a shrill pipe, but they took no notice whatever; nor did a set of tuning-forks, which I tried on a subsequent day, have any more effect. These tuning-forks extended over three octaves, beginning with A below the ledger-line. I also tried with my voice, shouting, &c., close to the head of a bee; but, in spite of my utmost efforts, the bees took no notice. I repeated these experiments at night, when the bees were quiet; but no noise that I could make seemed to disturb them in the least. In this respect the results of my observations on bees entirely agreed with those on ants."