1978] Lubin, Eberhard, & Montgomery — Miagrammopes 21 
cific kinds of prey (Eberhard 1977b), but the wide variety of cap- 
tured prey rules out this prey capture technique for Miagrammopes. 
Summary 
The webs of six species of Miagrammopes (Uloboridae) studied 
in Panama, Colombia, Costa Rica, and Venezuela have only one 
or a few sticky capture threads. Miagrammopes simus and M. sp. 2 
have one vertical capture thread attached to a non-sticky, hori- 
zontal resting thread. Miagrammopes sp. 1 (ca. unipus) builds 
from 1 to 5 near-vertical capture threads, and M. intempus, M. 
sp. 3, and M. sp. 4 use one or more capture threads that vary in 
their spatial arrangement. Webs are pulled taut by pulling in silk 
with either the front legs or the hind legs or both. The spiders as- 
sume highly cryptic postures during the day as they rest on their 
webs or near the egg sac. 
Attack and prey capture behavior in all species involves rapid 
jerking and sagging of the capture thread by the spider, resulting 
(in at least two species) in the prey becoming entangled in one or 
more loops of sticky thread before the spider arrives to attack. 
Second instar spiderlings of M. sp. 1 do not disperse, but moult 
a second time on the surface of the egg sac. Thus they construct 
webs only after they have fully formed calamistra and cribella and 
are capable of producing sticky silk. A mature female M. sp. 1 
constructed nocturnal egg sac webs that were reminiscent of small 
uloborid orb webs. 
The adaptive advantage of the reduced web of Miagrammopes 
is unclear. Many species of small insects are taken as prey and 
chemical attractants do not seem to be used. 
Acknowledgements 
Brent Opell kindly identified the spiders and reviewed the manu- 
script. Larry Kirkendall provided records of prey from Bayano, 
Panama. We are grateful to the following institutions and persons 
for their help and cooperation: Central Hidroelectica Anchicaya 
and Dr. Victor Manuel Patino of the Jardin Botanico in Mate- 
guadua (Colombia), Dr. Carlos E. Valerio of the Universidad de 
Costa Rica, and the Ministerio de Recursos Naturales Renovables 
(Venezuela). This work was supported by the Smithsonian Tropi- 
cal Research Institute and the Comite de Investigaciones of the 
Universidad del Valle. 
