148 
Psyche 
[Vol. 87 
Fig. 10. Construction of a sticky ball. A. Spider moves horizontally, waving her 
front legs actively in the space where she will produce and swing her bolas. Probably 
this behavior serves to sense the presence of objects which would interfere with hunting 
behavior. B. Spider hangs from the horizontal trapeze line and begins to pull sticky silk 
from her spinnerets onto the bolas line which is attached above to the trapeze line. C. 
Spider continues to produce sticky silk and the sticky ball grows. D. The last of the 
sticky silk has been produced and it is slowly absorbed into the ball as the ball hangs 
free. The spider then walks across the trapeze line, grasps the bolas line, and assumes 
the hunting posture. 
