HUMBLE BEES THEIR HOUSEKEEPING. 199 



that they borrowed the idea of the barb from the insect. 

 What we see with the unaided eye is simply the sheath 

 of the sting. 



Many savages poison their spears and arrows. But 

 the sting is infinitely superior to the arrow poison. No 

 poison that has yet been made, not even the terrible 

 wourali, or curare, as it is sometimes called, can retain 

 its strength after long exposure to air. The upas poison 

 of Borneo, for example, loses its potency in two or three 



CARDER BEE3 AT WORK. 



hours. But the venom of the sting is never exposed to 

 the air at all. It is secreted by two long, thread-like 

 glands, not nearly so thick as a human hair, and is then 

 received into a little bag at the base of the sting. When 

 the insect uses its weapon, it contracts the abdomen, 

 thereby forcing the sting out and compressing the 

 venom-bag. By the force of the stroke which drives the 

 sting into the foe, its base is pressed against the venom- 

 bag, and a small amount of the poison driven into the 

 wound. As a rule, if the bee or wasp be allowed to 

 remain quiet, it will withdraw its sting, but as the pain 



