Sting of the Honey Bee, 7 



has commonly been called the sheath, because it was sup- 

 posed to enclose, like a scabbard, the two darts or lancets. 



The sheath, in this view, is conical in form; the base being 

 anterior, directed toward the head of the insect, and its apex 

 posterior, 



A lateral view, however. Fig. 3 A, shows the anterior por- 

 tion to be cylindrical, but contracting on the upper side oppo- 

 site the point c, diminishes gradually to the extremity, near 

 which are two lateral teeth seen in the greatly enlarged 

 view, Fig. 13 b b. 



The sheath is double throughout its whole extent. The ex- 

 terior and interior walls, which, in a rudimentary state, form 

 two separate pieces, are firmly united at their edges, and in 

 the cylindrical portions of the sheath are nearly in juxtaposi- 

 tion, forming, in .lateral view, the oblong valve-chamber A, Fig. 

 3, but the inner wall abruptly contracting at c. Fig. 3, leaves a 

 lunate space above it, as shown in the transverse section at 

 this point. Fig. 7 n. A cross section at the point P, Fig. 3, is 

 seen in Fig. 6. Between the walls at this point, and also 

 throughout the entire cylindrical portion, there is an enclosed 

 space shown at n. Fig. 6. At the point c, Fig. 3, where the 

 contraction is seen, the space n begins to alter its form, and 

 this alteration continues down to the apex, where the two walls 

 unite. Several successive stages of this alteration are shown 

 in Figs. 7 to 9 at n. It will thus be seen that n, Fig. 7, is 

 a continuation of the smaller space n in Fig. 6. 



It will be observed that n, Fig. 7, has no connection with a. 

 Fig. 6, so that the poison injected into the cylindrical base of 

 the sheath follows the channel a. Figs. 7 to 9, between the 

 lancets. 



Near the base of the sheath, on the inferior side, arise two 

 flexible arms, b b. Fig. i, which curve in arcs of a circle in a 

 lateral and dorsal direction to their articulations e e, with the 

 powerful levers D D. 



The cylindrical part of the sheath is cleft along the lower 

 side, and this cleft, taking the form of a shallow groove, con- 

 tinues to the end. 



Lying in contact, in this groove, and along the inner margins 

 of the cleft, are the two lancets, their barbed edges k k ex- 

 tending laterally over its sides, and following the curve of the 

 arms before mentioned, are attached at c c, their anterior ex- 



