1974] 
Valerio — Drymusa dinora 
285 
a trap after the prey’s arrival in the web, and prey-wrapping is car- 
ried out exclusively by movements of the abdomen and without using 
the appendages. Prey is treated in a different manner according to 
size and perhaps other qualities, as also occurs in other groups of 
web-building spiders (Eberhard, 1967; Robinson, 1969; Shear, 
1969). 
Attack on small prey: The spider rests in the center of the web 
( B in figure 1 ) near the superior edge of the crevice or tunnel. 
When small prey (less than % the size of the spider) enters the 
tangled threads, the spider moves and attacks directly with the cheli- 
cerae and holds on firmly until the prey stops moving. Usually the 
prey is then carried to the resting site and feeding starts immediately 
without previous wrapping in silk. The arrival of a second item of 
prey does not elicit a response from the spider. 
Attack on large prey: When large prey penetrates at one side 
(C in Figure 1), the spider runs to A and starts immediately spin- 
ning a horizontal partition. The prey then moves through the 
tangles of the center towards the trap web. If the prey cannot cross 
this barrier of dry silk and starts heading back, the spider moves 
ahead of it to C where it builds another vertical web, thus enclosing 
the prey in a silken trap. Then, the direct attack begins. The spider 
approaches its victim with certain caution and suddenly strikes five 
or six times with the chelicerae at intervals of one second. Some- 
times, some chasing is involved. After the envenomation the prey 
may move around the web but the spider usually ignores it. Once 
the prey slows down (apparently due to the effect of the venom), it 
is wrapped in silk. 
The silk is distributed by oscillatory movements of the whole body, 
reinforced by more pronounced side movements of the abdomen (with 
conspicuous flexions of the pedicel), changing position at intervals 
to deliver silk to different parts around the prey. No appendages 
(other than the spinnerets) are involved in the process. The prey- 
is carried in the chelicerae to the upper portion of the web where 
wrapping continues for a few seconds. This post-immobilization 
wrapping seems to facilitate transportation of the prey to the resting 
site and attachment to the web for later feeding (Robinson et ah, 
1969). Once the prey is wrapped, the spinnerets are carefully 
cleaned by back and forth movements of the distal third of the 
fourth metatarsus. Later, the fourth metatarsi, are, in turn, cleaned 
by the chelicerae. 
Very large or very strong prey items entering the web do not 
produce an aggressive response from the spider. It simply lies flat 
