STING STRUCTURE. 
79 
which extend in groups forward to the lower segments 
of the abdomen, the plate d being fixed by a ligament 
connected with the curved arm above. 
By the contraction of the muscles the levers turn 
on the points o, and the curved arm being straightened 
and shortened, the sheath and attached lancets are 
projected. By a contraction of the muscles of c, turn- 
ing as it does on <?, its only point of attachment to d, 
the point i is raised, and the lever b, which turns on o, 
is tilted over, and causes the lancet articulated to 
its movable arm at c to slide along the groove towards 
and thus project its point into the wound beyond. 
Hyatt (71) says that by allowing a bee to sting 
a soft piece of leather an excellent opportunity is 
afforded for studying certain parts of the action and 
mechanism, for the whole apparatus, including the 
poison gland, will be beautifully dissected, the bee 
not appearing to be seriously injured by the loss. 
These movements, which can be easily seen, are of 
course reflex, because they continue for some time 
after the organ has been removed from the body of 
the bee. and bee-keepers will now understand why a 
bee apparently dead for some hours is able to sting. 
The venomous effect of a wound made by a sting 
is entirely due to the poison introduced by it, or we 
could not feel the pain we do by the mere thrusting 
in of the dart --J-oth of an inch in diameter to a depth 
of -/o^h of an inch. 
The poison is secreted from the blood in the 
cellular glands (^, Fig. 34) attached to the poison sac 
(/), which commence in a single tube bifurcating, and 
