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with and without a ball; another slightly larger one hunted without; 
and numerous newly emerged spiderlings appeared to hunt without. 
Perhaps this tendency is related to the fact that drying out of the 
sticky ball (see Fig. 14 and below) would be a more serious problem 
for smaller spiders due to surface-volume relations. 
As noted in Eberhard (1977), hunting spiders generally positioned 
themselves on the trapeze line with their ventral surfaces downwind. 
Since the direction of the wind at the study site varied erratically, the 
spiders assumed angles varying from 0° to 90° with respect to the 
trapeze lines. On two occasions when the wind changed 180°, the 
spider responded by releasing the ball and changing her position to 
hold it with the other leg I, changing her orientation 180° as she did 
so. 
Both those spiders with balls and ones in hunting position without 
balls responded to my humming (but not to the high-pitched hum of 
an electronic flash), suggesting that sound was not sensed through the 
bolas line as suggested by Gertsch (1947). The responses were 
different however. Spiders with balls extended one or both legs I, 
especially the lower one which was generally either extended laterally 
to point straight down, or else “cocked” ready to swing the ball (see 
Fig. Id in Eberhard 1977). Occasionally they actually swung the ball 
with a quick ventral flick of the leg. Those without balls sometimes 
flexed their legs I quickly, and other times extended them, especially 
the lower of the two. Even in the absence of sudden noises spiders 
holding balls twitched and jerked their legs I almost continuously, 
especially the upper one, giving the impression that they were 
extremely alert. Although the upper leg I seemed to be in position to 
grab prey, this was not its function since photos of spiders in the act of 
swinging the ball (Fig. 12) show this leg held back and away from the 
prey. 
Despite the spiders’ extremely quick reaction time and tne 
relatively slow flight of approaching moths (Eberhard 1980), it was 
not easy for the spiders to hit them, and 12 of 21 strikes I observed 
were misses. Most of the moths left after a miss and apparently did 
not return. When a spider succeeded in hitting a moth, the ball always 
stuck tight despite the moth’s struggles, and the spider descended the 
line, embraced the moth with her legs, and bit it. After several seconds 
she released her hold and wrapped the prey with slow alternate 
strokes of legs IV. The prey was rotated slowly or (usually) not at all 
during the wrapping. The spider then ascended the line as she held the 
