46 
Psyche 
[Vol. 89 
wrapping while hanging there by her spread legs I. 
The eggsacs were different from those described for any other 
uloborid. They were pure white, 2-3 mm diameter spheres with 
projecting spikes, and resembled the heads of maces; they were 
suspended in the plane of the orb portion of the web on a radial line 
(Figs. 13a, b). 
Discussion 
While the webs of all five species are similar in having more or less 
horizontal orbs with cones below, the details are strikingly different. 
The cones of U. conus, U. albolineatus, U. bispiralis, and U. #2702 
have a sticky spiral while those of U. trilineatus and C. parvus do 
not. In U. albolineatus, U. bispiralis, and U. sp. #2702 both the 
outer (rim) and inner portions of the orb have sticky spirals, while in 
U. conus the main capture surface is the rim sticky spiral and only 
occasionally is a sticky spiral present in the inner orb. The “orbs” of 
Conifaber parvus have no sticky spiral, but the dense mat serves as a 
trapping surface, as in uloborid “baby webs”. Orb-plus-cone webs of 
U. trilineatus have no sticky silk at all. 
The function of the cone in webs of all four species is probably 
primarily defense of the spider at the hub against predators and 
parasites. The cone forms a “cage” of threads around the spider, and 
a defense function is suggested both by the fact that U. conus and 
Conifaber parvus drop from the orb and hang inside this cone when 
disturbed or when the web becomes visible in sunlight, and by the 
fact that construction of conewebs by U. trilineatus occurs only 
when the spiders are about to enter the particularly vulnerable 
moulting period. The sticky threads in the cones of U. conus and U. 
albolineatus and U. #2702 sometimes trap prey (some U. conus webs 
have almost no other sticky lines), but the fact that the cones of U. 
conus, U. albolineatus, and U. bispiralis have only a few, irregularly 
spaced sticky spiral loops while those of U. trilineatus and C. parvus 
lack sticky threads suggests that prey capture is a secondary 
consequence rather than a primary function of at least some of the 
cones. Placement of sticky threads in cones could have evolved as an 
additional defense of the spider against predation or parasitism. 
The uloborid cones resemble the barrier meshes made by the 
araneid Nephila maculata (Robinson and Robinson, 1973) at one or 
both sides of their more-or-less vertical orbs; in young N. maculata 
