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Psyche 
[Vol. 90 
sites were shaded, and only rarely was a web placed in an area that 
received direct sunlight. Various web support structures were util- 
ized, including leaf tips, herbaceous stems, woody vines and 
branches, and palm fronds. The circular webs averaged 21.6 cm in 
diameter and 350 cm^ in catching area (n = 8). 
Individuals do not appear to remain at a particular web-site for 
more than 1-2 days. On August 3 I marked the location of 20 
occupied webs. These sites were then revisited daily for 7 days, and 
the presence or absence of the spider and the web was recorded. In 
terms of the number of spiders remaining at their initial site, the 
results obtained were as follows: Day 1 — 12; Day 2 — 3; Days 3 and 
4 — 2; Days 5 and 6 — 1 ; Day 7 — 0. In no instance was a spider absent 
but the web present; spider and web were always both present or 
both absent. In addition, in examining a 2 m-3 m radius about each 
vacated web-site, I never observed the presence of a newly con- 
structed web. 
Five prey categories comprised 89.0% of the total sample, and 
vertical abundance patterns were examined for these groups only. 
Beetles, parasitoid Hymenoptera, nematocerous and non- 
nematocerous Diptera all exhibited a similar trend in vertical abun- 
dance (Figure 1). That is, the greatest numbers of individuals were 
collected at the two lowest sampling heights (0.3 m and 0.6 m). 
While similar numbers of parasitoid Hymenoptera were captured at 
the two lowest sampling heights, nearly twice as many beetles, nema- 
tocerous and non-nematocerous Diptera were captured at 0.3 m 
than 0.6 m. Ants were captured in relatively constant numbers over 
all sampling heights. 
Although the numbers of trapped individuals varied greatly with 
height for 4 prey categories, each major category comprised a rela- 
tively constant proportion of the total sample at each height (Figure 
2). Similarly, within each category size frequency distributions did 
not vary with height in any obvious manner (Figure 3). Thus, while 
the abundance of flying insects varied with height, the taxonomic 
and size composition of this fauna did not. 
The vertical distribution of A. tuonabo did not closely match that 
observed for available prey (Figure 4). Alpaida tuonabo preferred 
web-sites between 0.6 m-1.2 m, and approximately 60% of the spi- 
ders measured were within this range. Thus, while traps nearest the 
ground caught the greatest numbers of flying insects, only 18% of A. 
tuonabo were found below 0.6 m. 
