438 HOUSEHOLD INSECTS 



is known as the alkaline gland. Both glands connect with 

 the bulbous portion of the sting and thence with the canal 

 in the center, so that the poison runs down this canal 

 directly into the wound made by the sting. The end of 

 the sting is barbed. Experiments by Carlet seem to 

 show that it is only when the acid and alkaline contents 

 of the two glands mix that a poisonous effect is produced. 

 He showed that flies artificially inoculated with the secre- 

 tion of either gland alone lived a long time, even in spite 

 of the necessary mutilation ; but when a fly was inocu- 

 lated with the acid secretion and then with the alkaline 

 secretion, it died in a much shorter time — supposedly 

 when the two secretions came together in the body. This 

 detailed description of a bee sting with its poison glands 

 will serve to convey some idea of the stinging mechanism 

 of the bees, wasps, and hornets, for they are probably all 

 similar, although perhaps differing in detail and in com- 

 plexity. 



Among the stinging Hymenoptera, the common ants 

 are too well known to need detailed description. The 

 females and the workers (undeveloped females) of many 

 ants possess stings furnished with poison glands. The 

 stings of ants, however, are not barbed and may therefore 

 be withdrawn from the wound. The mound-building 

 prairie ant of the West and the agricultural ant of Texas 

 sting severely when molested. Some ants can bite sharply 

 with their jaws, at the same time injecting formic acid 

 into the wound. 



The cow-killer ants or velvet ants of the South and 

 Southwest are usually brilliant insects with red and black 

 bodies densely clothed with hair. They have a very large 

 sting and can inflict severe and painful wounds. As the 



