THE EXTERNAL STRUCTURE OF AXTS. 29 



that the ninth segment appears to bear two pairs of appendages. In 

 the Ilymenoptera the ovipositor is still retained with its Orthopteroid 

 function in certain families like the ichneumons and gall-Mies, which 

 oviposit in the tissues of insects and plants. In the bees, wasps and 

 ants, however, the organ has lost this primitive function and has 

 become an organ of defence. Its embryological origin in these forms, 

 however, is the same as in the Orthoptera. Dissections of the sting 

 of the pupal and adult ant show that the pairs of appendages become 

 closely applied to one another so that they appear as a single organ. 

 The appendages of the tenth segment actually fuse to form a single, 

 pointed, grooved piece, the gorgeret ( Stachelrinne ) which encloses the 

 pair of appendages belonging to the eighth segment. These are very 

 slender and pointed and are known as the stylets, or prickles (Stech- 

 borsten). The appendages of the ninth segment become somewhat 

 lamelliform and, without fusing with each other, enclose the gorgeret 

 as the sting-sheath ( Stachelschiede). In stinging, the pointed gorgeret 

 is thrust into the skin and then the stylets are alternately pushed deeper 

 into the wound beyond the tip of the gorgeret which they do not sur- 

 pass when the sting is at rest. The duct of the gland that supplies the 

 poison, which produces the burning sensation, enters the base of the 

 gorgeret. The stylets are smooth and not barbed on their sides as 

 they are in the bee ; hence the ant is able to withdraw its sting from 

 the wound. While the sting is very large and well-developed in the 

 Ponerinse, Dorylinas and most Myrmicinse, it is vestigial or absent in 

 the other subfamilies. 



At the tip of the male gaster there are three pairs of rather com- 

 plicated appendages forming the genital armature. They are devel- 

 oped on the ninth abdominal segment, /. c., the segment which in the 

 female gives rise to the sting sheath. The sternal plate of this segment, 

 which in the male lies in front of the appendages, is known as the 

 annular lamina (Fig. 19, la). The three pairs of appendages enclose 

 one another, so that we may distinguish an outermost, a median and 

 an innermost pair. The outermost pair has been called the stipites 

 (st). The median pair is sometimes more or less completely divided 

 into two pairs, known as the volsellae (v) and lacinige respectively; and 

 the whole group of appendages comprising the stipites, volsellse and 

 lacinise are known as the external paramera ( Verhoff and Emery). 

 The innermost pair alone is known as the internal paramera. They 

 are closely applied to each other in the median sagittal plane of the 

 body and function as a penis (/>). During copulation the stipites. 

 which are large, robust and often covered with hairs, function as 

 claspers. The volsellae and laciniae, which are smaller and less heavily 



