ANATOMY OF THE BEE. 



605 



A close examination of the sting proper 

 shows that both the bnlb and the tapering 

 shaft are formed of three pieces. One is 

 dorsal {SliB and ShS) while the other two 

 (Let) are ventral (of course only one of the 

 latter shows in side view). Furthermore, 

 the basal arm on each side is formed of two 

 pieces, one of which [ShA) is continuous 

 with the dorsal piece of the sting, while the 

 other (Lei) is continuous with the ventral 

 rod of the same side. Since these ventral 

 rods are partially enclosed within a hollow 

 on the under side of the dorsal piece, the lat- 

 ter is called the slieath of the stlrtg. It con- 

 sists (f the terminal shaft of the sheath 

 iShS), the biilh iShB), and of a basal arm 

 [ShA) on each side. The ventral pieces [Let] 



Vx P 



tubular, alkaline gland (BGl). By move- 

 ments of the triangular jilates (Fig. 5, Tri) 

 the lancets slide back and forth against tlie 

 sheath while the poison exudes in tiny drops 

 from an opening between them near the 

 tips. The poison-sac has no muscles in its 

 walls, and, hence, can not force the poison 

 through the sting. The poison, in fact, is 

 driven out of the latter by a force-pump 

 inside of the bulb. This consists of two 

 pouch-like lobes situated on the upper edges 

 of the lancets, having their cavities open 

 posteriorly. When the lancets move forward 

 the walls of these pouches collapse; Ijut when 

 the motion is reversed they tlare apnrt and 

 drive the poison contained in the bulb back 

 through the shaft and out at the end. 



Vx, ten 



Ant 



PrbFs 



Gl/li Pgl 



From Bulletin No. 18, "The Anatomy of the Ho, ey bee/' by Snodgrasp. Bureau ot Ent., Dept. of Ag., Washington, D. C. 



FIG. 3.— Head of worker with parts of proboscis cut off a short distance from their bases. A. anteiior: 

 B, posterior; «, cl.ypeal suture; Anf, antenna; b, pit in clypeal suture mat Ising anterior end of internal 

 bar of liead; r, pit on occipital surface of head, marking- iiosterior end of internal bar; Cd, cardo; Vip, 

 Clypeus; B, compound eye; For, foramen magnum; Ft, front; Ge, gena; Gls, glossa. or "tongue; 

 ;f, ventral groove of glossa; ib, labium; LhPlp, labial palpus; Lm, labrum; Md, mandible; Mf, ment- 

 um; Mth, mouth; Mr, terminal blade of maxilla; MxPlp, maxillary palpus; O, ocelli; Of, occiput: i^ff'', 

 postgena; P^^paraglossa; PrZ), base of proboscis; P/bFs, fossa of proboscis; Smf, submentum; &t, stipes; 

 ten, sma'l bar of tentorium arching over foramen magnum; Vx. vertex. 



are slender sharp-pointed rods having barb- 

 ed extremities, and are known as the lancets. 

 The shaft of the sheath is grooved along the 

 entire length of its ventral surface, the 

 groove enlarging into a spacious cavity in 

 the bulb. The lancets lie close together 



The poison is an acid liquid formed by the 

 glands (Fig. 8, AOl AGl, and Bijl). Two of 

 these [AGl and AOl) are simply small en- 

 largements at the ends of two long coiled 

 tubes [AGID], which latter unite into a shoit 

 single tube that opens into the anterior end 

 against the ventral edges of the sheath, but I of the great poison-sac {FsnSc). The seere 



slide freely upon minute tracks on the latter. 

 The tliree parts, therefore, inclose between 

 them a cavity which is tubular in the shaft, 

 but enhirged into a wide chamber in the 

 bulb. The great poison-sac (Fig. 8, Psn Sc) 

 of the acid-glands of the sting opens into 

 the base of the bulb along with the smaller, 



tion of these glands is acid. The tliird gland 

 [BGl] is a short, somewhat twisted tube 

 opening into the bulb of the sting along 

 with the poison-sac. Its secretion is alka- 

 line. Cnrlet has shown that it is only the 

 mixture of these two secretions that has the 

 full strength in stinging properties. 



