THE ABDOMEN, WAX GLANDS, AND STING. 77 



between two different organs — in fact we can not doubt that the sting 

 is simply an ovipositor which, being no longer needed for egg-laying 

 purposes, has been modified into a poison-injecting apparatus. Zan- 

 der (1899, 1900) and others have shown that the sting of the bee 

 arises from six little abdominal processes of the larva, two of which 

 arise on the eighth segment and four on the ninth. Those of the first 

 pair develop into the lancets, those of the middle pair on the ninth 

 segment fuse to form the sheath, while those of the outer pair, be- 

 come the palpi. The ovipositor, it will be remembered, develops in 

 the lower insects from two pairs of processes arising on the eighth 

 and ninth abdominal sterna, the second pair of which very soon 

 splits into four processes. The simultaneous appearance of six on 

 the bee larva is simply an example of the hurrying process or accelera- 

 tion that the embryos and young of most higher forms exhibit in 

 their development. 



It is only the higher members of the Hymenoptera, such as the 

 wasps and the bees and their close relatives, that possess a true sting. 

 The females of the lower members have ovipositors which closely re- 

 semble those of such insects as the katydids, crickets, and cicadas, but 

 which, at the same time, are unquestionably the same as the sting of 

 the stinging Hymenoptera. It is said that the queen bee makes use 

 of her sting in placing her eggs in the cells, but both the wasps and 

 the bees deposit their eggs in cells or cavities that are large enough to 

 admit the entire abdomen, and so they have but little use for an egg- 

 placing instrument. But the females of the katydids and related 

 forms like Gonocephalus (fig. 8) use their ovipositors for making a 

 slit in the bark of a twig and for pushing their eggs into this cavity. 

 The cicada and the sawfly do the same thing, while the parasitic 

 Hymenoptera often have extremely long and slender piercing oviposi- 

 tors for inserting their eggs into the living bodies of other insects. 



An examination of the sting in place within the sting chamber, as 

 shown by figure 41, will suggest what the accessory plates represent in 

 other less modified insects. It has already been explained that the last 

 external segment of the female abdomen (fig. 32, VII) is the seventh. 

 Within the dorsal part of the sting chamber is a slight suggestion of 

 the eighth tergum (fig. 41, VIIIT), which laterally is chitinized as a 

 conspicuous plate bearing the last or eighth abdominal spiracle {Sp) . 

 The triangular plate (Tri), as Zander has shown by a study of its 

 development, is a remnant of the eighth sternum, and the fact that it 

 carries the lancet (Let) shows that even in the adult this appendage 

 belongs to the eighth segment. The quadrate plate (Qd), since it is 

 overlapped by the spiracle plates of the eighth tergum, might appear 

 to belong to the eighth sternum, but Zander has shown that, by its 

 development, it is a part of the ninth tergum. In many other adult 

 Hymenoptera, moreover, the quadrate plates are undoubtedly tergal, 



