138 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 



Fig. 47. — Mechanism of the sting of Apis mellifica, worker. 



A, mesal view of right half of sting apparatus with shaft partly depressed, 

 showing anterior and posterior muscles {17, 18) of second valvifer, muscles of 

 furcula (/p), and ramus muscle {20). 



B, the shaft in usual position, with ramus muscle {20) contracted. 



C, the shaft depressed by contraction of furcula muscle (/p). 



h, ventral articulation of first valvifer on second valvifer; Frc, furcula; IXT, 

 tergal plate of ninth segment (quadrate plate) ; IXV, venter of ninth segment; 

 rivl, ramus of first valvula ; r2vl, ramus of second valvula; Stng, shaft of sting; 

 3VI, third valvula; 2VIJ, second valvifer (oblong plate) ; a, basal articulation 

 of shaft on ramus of second valvula. 



