246 
Psyche 
[Vol. 95 
which have fallen on the water surface elicited a different prey catch- 
ing behavior. Capture attempts were made after reorientation of the 
spread front legs towards the source of waves and motionless peri- 
ods of varying length. The spiders responded to close stimuli (within 
6 cm) by jumping on the prey. More distant prey (6-25 cm away) 
was reached by “rowing”: the front legs remain spread out on the 
water surface at a fixed angle, while legs II and III perform rowing 
motions, pushing the spider forward. The IV pair remains extended 
on the water. 
Since the spiders did catch ants (but dropped them quickly) and 
hunted regularly at night, chemical and visual stimuli are probably 
not involved in prey detection. 
T. spinosissimus chewed its prey with the chelicerae, turning it 
with the aid of its pedipalps. While feeding, the spiders frequently 
discharged clear drops of liquid from their anus. 
Mating behavior (twelve matings observed) 
Two to four weeks following the final molt, the females stopped 
hunting and spun a loosely woven three-dimensional mesh (mating- 
web). While resting in the web, the females hung upside down and 
assumed a distinct posture: all femora were held upright, the patel- 
lae nearly touching each other above the prosoma; tibiae and meta- 
tarsi were bent downwards. 
Males did not hunt after the final molt but built small triangular 
sperm webs during the night. Charging of the palps was not 
observed. Males responded to threads from mating-webs placed in 
their aquaria with courtship behavior by touching and hitting the 
threads with their front legs. Threads of subadult females did not 
elicit courtship behavior. 
Males reaching a mating-web initiated courtship by pulling at the 
threads with their pedipalps and beating them with their front legs. 
Intense trembling of the male opisthosoma was observed. The 
female’s response consisted of pulling at the threads with her palps 
and front legs and enforcing her “resting” posture. Once the female 
responded, the male entered her web and continued his courtship. 
After each female response, the male moved closer to the female 
until he reached her. Courtship lasted 3 to 75 minutes. 
The male touched the female’s prosoma first with his front legs, 
then beat rapidly at the female’s opisthosoma. The male climbed 
onto the female from the side and positioned his prosoma over her 
