88 INJURIOUS AND USEFUL INSECTS 



If a pane of glass is wetted with the breath, or dusted with 

 fine flour, no insect can climb up it. 



The sting of the bee is too remarkable to be passed over, 

 but its structure is complex, and cannot be understood except 

 by those who will take some trouble. If we remove the integu- 

 ment from the under side of the last exposed segment of a 

 worker-bee, we see a whitish, conical mass, enlarged in front — 

 i.e. towards the head of the insect, and tapering behind. This 

 is the sting. The hard, piercing parts, which are dark-coloured, 

 are enclosed between a pair of fleshy prominences (right and 

 left) which form the sting-palps. The base of the sting 

 consists of two rounded masses of muscles, in each of which 

 we can discover, with the aid of a lens, two curved, dark- 

 coloured, chitinous bands. With the point of a needle the 

 central part, or sting proper, can be separated from the 

 sheath, and parted into three. The central part may be 

 called the guide, for reasons which will shortly be given, and 

 the pair of slender pieces, one on either side, the daxts; all 

 three are hard, finely pointed, and barbed towards the tip ; the 

 guide being barbed on both sides, but the darts only on the 

 outer sides. By cutting a section through the whole, which 

 is by no means an easy thing to do, owing to the hardness of 

 the guides and darts, their disposition can be better under- 

 stood. It will then appear that the guide is three-cornered, 

 with two convex and one concave side. The concave side 

 is turned downwards. Running along it, and near its edges, 

 are two parallel headings, upon which slide corresponding 

 grooves sunk in the darts. Each dart has its own groove, 

 which glides smoothly upon the beading. Between the guide 

 and the two darts a channel is enclosed, along which fluid 

 poison, drawn from a poison-bag at the base of the sting, can be 

 forced. Beyond the guide, the poison is enclosed by the darts 

 alone. Though the wall of the channel is formed of sliding parts, 

 the fitting is so true that no fluid escapes except at the further 

 end, where it passes out by several pores close to the bases of the 

 barbs. It may next be pointed out that the guide branches 

 towards its base into two slender, curved arms ; each dart is 

 also prolonged at its base into a curved, slender arm, and these 

 four arms are the dark-coloured chitinous bands already seen 

 at the root of the sting, where the muscles which actuate them 

 are collected. 



