1967] 
Eberhard — Diguetid Spiders 
177 
the retreat and grappled with it. 2 If the prey was active (a moth 
for example), there was often a struggle lasting several seconds 
before the spider was able to grip it securely with the chelicerae, 
and the prey often escaped at this stage. Legs I were commonly 
thrust through the platform and their tarsi brought down on top 
of the prey, pressing it firmly against the platform and bringing it 
close to the chelicerae. 
Biting and poisoning behavior was usually released only if the 
prey struggled. Only underfed spiders bit immobile prey. When 
a recently killed cockroach was dropped onto the platform, the spider 
rushed to it and grabbed it with legs I (and II?), but did not bite 
it. When the roach was pulled gently with forceps, the spider bit 
it. Objects which did not move within about 5 minutes of contact 
were pulled through the platform (see below) and dropped. Death- 
feigning insects may thus sometimes avoid capture. 
Once the spider had a good grip with the chelicerae it held on 
until the prey’s struggles subsided (usually about 10 minutes after 
the attack for prey about 1/2 the spider’s size). If the prey was 
strong it sometimes pulled the spider around a bit before the poison 
took effect. All eight of the spider(s legs were used to maintain its 
grip on the platform when this happened. 
About five to ten minutes after the attack the spider slowly dis- 
engaged the prey (usually still twitching) from the web, pulling it 
through a slit in the platform made by breaking some strands and 
pushing others aside. Lines were cut by bringing them to the 
mouth region with tarsi III (and II?). Once when the prey was 
quite large in relation to the spider, the spider attached a line to 
the platform threads and then fixed this line to the prey before 
releasing its hold with the chelicerae to begin removing the prey 
from the web. This line anchored the prey more securely as the 
disengagement process began. 
Often, especially when it was large, the prey got stuck as it came 
through the platform, and the spider tugged and pulled at it until 
it came free. Most, if not all, movements involved in freeing the 
prey from the web were accompanied by movements of the abdomen 
"If the prey was entangled in the lines above the platform, the spider 
shook the web violently several times, sometimes causing the prey to fall 
onto the platform. If the prey did not fall, the spider sometimes climbed 
into the mesh to attack it there. The holes in the platform near the mouth 
of the retreat were occasionally used to gain access to the upper mesh, as 
Cazier and Mortenson (1962) supposed. Other times the spider climbed 
around the outer edge of the platform and into the upper mesh. 
