STING STRUCTURE. 193 



free play upon each other, while the sting itself 

 has as little contact with the venom as a duck's 

 back with water. The extrusion of the sting brings 

 forward this secretion, which emits the peculiar odour 

 sometimes to be recognised if a number of bees are 

 roused to anger. When the poison is examined 

 through a good objective, the tiny oil globules which 

 have been provided by the lubricating gland are found 

 in thousands. Not only is the clogging of the moving 

 parts prevented by this beautiful system of lubrica- 

 tion, but that friction is greatly reduced which 

 tells so terribly against long rods moving in grooves, 

 especially such as these, only ^-—in. in diameter, 

 and fully 600 times as long as broad. And here I find 

 the very highest degree of mechanical perfection 

 is reached, by not permitting the rod to move in 

 absolute contact with its groove throughout its whole 

 length ; for if the rods, at their upper parts (near 

 c, c ', A, Plate VI.), be torn from their places, they 

 will be found to carry studs, or cogs, at regular 

 intervals, which themselves only come against the 

 back and sides of the grooves, so that they not only 

 diminish the contact surfaces, but act as distributors 

 of the lubricant — an antitype of the plan often 

 followed in machinery required to act with great 

 smoothness and precision. It must, however, here 

 be noted, that good high power objectives are re- 

 quired. 



The sting of the queen differs from the worker's 

 in many particulars, although the plan of the struc- 

 ture of both is identical. The worker uses her 

 weapon at great risk to herself, for frequently, and, 



