410 
Psyche 
[December 
Table 1. Prey found being fed on by Argyrodes attenuatus in the field. 
Mature and penultimate 
females 
spiderlings 
2 small juv. sparassids 
18 small flies (5 Cecido- 
1 imm. salticid 
myidae, 1 Mycetophilidae, 
1 imm. ctenid (?) 
12 ? other Nematocera) 
1 penult. Theridiosoma (?) 
1 tiny spiderling 
3 (?) 
allowed to grab one of the lines of the web of a mature female A. 
attenuatus about 50 cm from where the spider was resting. The 
spiderling rested immobile, after I cut its trail line, while the A. 
attenuatus advanced toward it slowly and smoothly. When the 
female was about 15 cm away, the spiderling began walking toward 
her along the line, and she suddenly began approaching more 
rapidly. Then, before she had reached the advancing spiderling, she 
quickly turned 180° and pulled a line of wet sticky silk from her 
spinnerets with her legs IV, apparently contacting the line with the 
outer surfaces of the tarsi (Figs. 2 and 3). The instant the spiderling 
came in range, she wrapped it in this thread with a quick movement 
of the hind legs, then bit it and wrapped it further in apparently dry 
silk. Finally she carried it dangling from her leg III to the place 
where she had been resting, and began to feed on it. 
Aggressive responses such as these were usually elicited when 
spiderlings were placed on occupied webs, but Philoponella sp. and 
Fig. 2. Mature female A. attenuatus attacking an immature ctenid walking on a 
line in its web. The female has drawn sticky silk (covered with small balls) with both 
hind legs, and is about to apply it to the spiderling. 
