PLATE 1.43. QUEEN STING. CLOSE-UP

TOP LEFT Distal tip of the sting apparatus showing the terminus of the venom channel. Two barbed lancets in the foreground oppose each other (earlier workers reported that the queen sting had no barbs). Behind the lancets is the troughlike stylet. When stinging, the lancets slide back and forth on serrated tracks (lower arrow). The tracks form the trough at the tip of the stylet. Each thrust pulls the sting deeper into the victim. Both the track and the groove in each lancet (not visible) are serrated, probably to reduce friction. Note the small "indentations" (one per barb) (upper arrow) on the lateral margins of each lancet (see the top right micrograph). In comparison with worker barbs, the queen barbs are less formidable, which may permit the queen to sting repeatedly without loss of the sting. Other work suggests that the queen sting is covered with a surface lubricant while that of the worker is not. (x 1,040)

TOP RIGHT Highly magnified view of the indentation indicated by the upper arrow in the top left micrograph. One indentation is associated with each barb on the lancets and stylet. This structure appears to be a campaniform sensillum. If so, such a proprioceptor might monitor pressure generated by the relative depth of insertion of the sting or flexion of the lancets. (x 15,000)

BOTTOM LEFT Everted lancets of the queen. The stylet is flanked by the two hairy lobes of the sting sheath. (x 188)

BOTTOM RIGHT Masses of cuticular hair fasicles internally lining the sheath lobes. (x4,688)