THE SPIDER GENUS ARIADNA IN THE AMERICAS (ARANEAE, DYSDERIDAE) JOSEPH A. BEATTY^ INTRODUCTION The spider family Dysderidae, to which the genus Ar'iadna belongs, is one of a series of presumably primitive families called the haplogyne spiders, from the simplicity of their genitalia. Other haplogyne families are the Plectreuridae, Diguetidae, Sicariidae, Scytodidae, Caponiidae and Oonopidae. (The families Leptonetidae, Ochyrocerati-dae, and Telemidae, often included in the haplogyne series, are possibly more closely allied to the Araneoidea, and are omitted from consideration here. ) Dysderids are medium-to large-sized spiders (maximum body length about 25 mm) of either sedentary or wandering habits. Their web is of the tubular retreat type, sometimes with radiating trip lines extending from the mouth, but containing no \iscid silk, and not functioning as a snare. The spiders have six eyes (or no eyes, as in a few cave-dwelling species), two lungs, and a pair of tracheal spiracles close behind the lung apertures; they bear usually three, sometimes two, tarsal claws. The family is nearly cosmopolitan in dis-tribution, but is absent or rare in polar and cold northern temperate regions. The genus Ariadna is of interest because of its almost worldwide distribution, its occurrence on isolated islands, the many species that have been described, and the fact that it is haplogyne. The genitalic ^ Department of Zoology, Southern Illinois Uni-versit)', Carbondale, Illinois 62901. Bull. Mus. C simplicity of haplogyne spiders makes iden-tification of specimens, especialh' females, difficult. As a consequence, the taxonomy of the haplogyne families has been in a confused state until recently. A revision of the American Ariadna was the principal objecti\e of this study, in which, as far as possible, the males were distinguished by genitalia. A secondary objective, however, was a search for other taxonomic characters. Computer methods were used in this search and in the grouping of species, and the calculated results were compared with those obtained by a "clas-sical" taxonomic approach ( Beatty and Bos-sert, in prep.). Although the secondary objective is probably of more general in-terest and application, all phases of the study are, of course, closely interrelated. ACKNOWLEDGMENTS This study was conducted undc^r the direction of Dr. Herbert W. Le\'i of the Museum of C'omparati\e Zoology. His advice, support, and encouragement have been of great assistance throughout the course of the research, and his patience \\ ith its protractedness is greatly appreciated. Professor F. M. Carpenter, in addition to serving as major professor, offered support in both academic and personal matters further than anyone has a right to expect. I am most sincercK' grateful to him for many favors. The excellent library and the collections of the Museum of Comparative Zoology onip. Zool., 139(8) : 4.33-518, June, 1970 433
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