A NEW QUASISOCIAL ANELOSIMUS SPIDER 
(ARANEAE, THERIDIIDAE) 
FROM PARAGUAY 
By Harold G. Fowler 1 and Herbert W. Levp 
Introduction 
The genus Anelosimus was last revised by Levi (1956, 1963). Since 
these revisions, considerable attention has been given to the study of 
the social behavior of spiders (Kullmann, 1968, 1972; Shear, 1970), 
and especially to the social behavior of species of Anelosimus (Brach, 
1977). One species, Anelosimus eximius, constructs communal webs 
that encompass many cubic meters (Simon, 1891), and is considered 
by Wilson (1971) to have reached the level of quasisociality. We now 
describe and provide observations on a new quasisocial Anelosimus 
from southern South America. 
Anelosimus lorenzo Levi, new species 
Figures 1-4 
Holotype. Male holotype and numerous female paratypes, all in 
poor condition, having once been dry, San Lorenzo, Paraguay, 
collection 25 July, 1976, (H. Fowler) in the Museum of Comparative 
Zoology. 
Diagnosis. The male of this species differs from Anelosimus 
rupununi Levi by the shape of the conductor in the palpus. No 
differences are known in females. 
Description. Female. Carapace brown with wide darker median 
longitudinal band. Sternum, legs brown. Dorsum of abdomen white, 
with a line of black patches. Sides dark. Venter black with white spots 
toward sides. White behind and above spinnerets. Anterior median 
eyes subequal in size, larger than posteriors which are 0.7 diameters 
of anteriors. Anterior median eyes 1.8 diameters apart, a third of their 
diameter from laterals. Posterior median eyes 2 diameters apart, 1.5 
'Department of Entomology and Economic Entomology, Rutgers University, New 
Brunswick, N.J. 
2 Museum of Comparative Zoology, Harvard University, Cambridge, Mass. 02138. 
The junior author is responsible only for naming and describing the new species. 
Manuscript received by the editor February 13. 1979. 
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