18 
Psyche 
[March 
Uloborids do not have functional cribella until after their first 
moult outside the egg sac (Wiehle 1931) and thus cannot produce 
sticky silk as newly emerged second instar spiderlings and cannot 
make functional, adult-type webs until after the second moult. Sec- 
ond instar spiderlings of Uloborus spp. spin orb webs made of dense 
sheets of fine threads, lacking the sticky spiral of the adult web 
(Wiele 1931, Szlep 1961, Eberhard 1977a). Spiderlings of M. sp. 1 
solve the same problem by going through the second moult on the 
outside of the egg sac before dispersing; they thus have functional 
cribella before spinning their first webs. 
Discussion 
The webs of the Miagrammopes species in this study are basically 
similar in having one or a few simple, sticky capture threads that 
are held under tension, sometimes with a few additional fine, non- 
sticky threads attached to them. The spiders’ attack behaviors all 
involve suddenly sagging the capture thread. Details of placement 
of the capture and resting threads, and the spiders’ web tensing 
behavior are variable among the species, and even to some extent 
among individuals of some species. Two of the characteristics de- 
scribed for M. sp. 1 appear to be unique among spiders — the 
double moult of the young before leaving the egg sac, and the 
special feeding web of the female near her egg sac. 
The web of Miagrammopes species from Natal was similar to 
some of the webs of M. intempus and M. sp. 3 in having a single 
horizontal capture thread without a separate resting thread (Aker- 
man 1932). The presence of additional fine threads attached to the 
capture thread was not noted in webs from Natal, but they would 
almost surely have gone unnoticed unless the webs were powdered. 
Web construction behavior was similar in the Natal species. The 
spider sat at one end of the completed capture thread, facing it; 
the thread may have been broken with the spider bridging the gap 
with its body (e.g. Marples 1962), but Akerman’s drawing shows 
an intact line. The thread was held under tension by pulling it in 
with legs IV as do all six species of this study and was also quickly 
sagged when prey hit it. The single, horizontal, capture thread web 
may represent a further simplification of an already simple web, 
with a single sticky thread taking the place of both the horizontal 
resting thread and the vertical capture thread. 
