PSYCHE 
Vol. 85 
March, 1978 
No. 1 
WEBS OF MIA GRA MM OPES (ARANEAE: ULOBORIDAE) 
IN THE NEOTROPICS 
By Y. D. Lubin 1 , W. G. Eberhard 2 , and G. G. Montgomery 1 
Introduction 
Uloborid spiders ( Uloborus sens, lat.) typically construct orb webs 
composed of non-sticky threads (radii, frame threads, hub, and 
temporary spiral) which support a sticky spiral made of cribellar 
or hackled silk. Specialization of the web in the uloborid genus 
Miagrammopes has involved the reduction of its structural com- 
plexity together with changes in its operation as an insect trap. The 
one described web of an unidentified species from Natal, South 
Africa is reduced to a single horizontal capture thread (Akerman 
1932). In this paper we describe the webs of six more species of 
Miagrammopes and the prey capture behavior of the spiders, re- 
vealing a substantial range of variation in simple web design within 
the genus. 
We studied M. simus on Barro Colorado Island, Panama Canal 
Zone during the wet season of 1976. At no time was this species 
common. In May and June, 1977, M, sp. 1 (ca. unipus) was studied 
in a bamboo ( Guadua angustif olia) thicket in the Cauca valley near 
Cali, Colombia where it occurred in abundance. In August, 1977, 
M. intempus Chickering and M. sp. 2 were found in Valle, Colom- 
bia. The former was common in some places on hanging moss on 
exposed roots and low branches near the Rio Anchicaya at 400 m 
elevation, while the latter was found in brush near the Rio Tulua 
at 1100 m elevation. A small tree in a clearing on Finca La Selva 
1 Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Panama 
Canal Zone. 
2 Departamento de Biologia, Universidad del Valle, Cali, Colombia, and Smith- 
sonian Tropical Research Institute. 
Manuscript received by the editor April 16, 1978. 
1 
