-- Records of the Western Australial1 Museum Supplement No. 52: 151-158 (1995). Two new species of social crab spiders of the genus Diaea from eastern Australia, their natural history and distribution Theodore A. Evans Department of Zoology, University of Melbourne, Parkville, Victoria 3052, Australia Abstract Two new species of social, Eucalyptus leaf weaving thomisids are described. Social Diaea are large for the genus; twice the size of solitary congenerics. D. ergal1dros sp. novo is found in sclerophyllous forests in Victoria, along the Great Dividing Range through New South Wales to Queensland. It is also found in Tasmania. D. megagYl1a sp. novo is found along the Great Dividing Range in New England, New South Wales and southern Queensland. The group living habit of these species appears similar to that of D. social is from southwestern Western Australia, and social behaviour and life history patterns of all three species are briefly compared and discussed. INTRODUCTION When the social thomisid Diaea socialis was first described by Main (1988), it was an anomaly among the social spiders; a taxonomically heterogeneous group united by all weaving a snare web (Buskirk 1981, but see also Downes this volume). In fact, the attributes of the snare web lead early workers to state that it was a necessary preadaptation for sociality to arise (Shear 1970). However, there are now two genera which do not weave a snare web; Delena cancerides Walckenaer (Heteropodidae) (Rowell 1985, 1987), and Diaea socialis Main (Main 1988; Rowell and Main 1993) and both are found only in Australia. Main (1988) described the natural history, behaviour, population cycles and taxonomy of Diaea social is from Western Australia. Subadult spiders collected from Victoria and Tasmania were included in this description, and a note about a social thomisid in southern Queensland (Brimblecombe 1962) was also mentioned. However, Main (1988) noted that "Further research may establish that there are several species involved." A long term study of the behaviour and ecology of social Diaca occurring on the eastern mainland and Tasmania revealed consistent differences from the Western Australian spiders. Comparison of the anatomy, life history and distribution demonstrates that there are three distinct species of Diaca in southern Australia. Two are new species distributed in the sclerophyllous Eucalyptus forests along the east of the continent and Tasmania. These two species are described here. METHODS Social Diaea from southeastern Australia are typically found in closed canopy forests of Eucalyptus species that have short, but slender leaves (e.g. messmate E. obliqua, broad-leaved peppermints E. dives, narrow-leaved peppermints E. radiata, yellow box E. melliodora). Locating the characteristic nests from the surrounding pendulous foliage was facilitated by their distinct ball shape. Collecting techniques varied: tall forests were surveyed by examining the canopies of felled trees immediately after falling, whereas low forests were searched by walking transects. Nests were collected either by climbing the tree, or by using secateurs on an extending pole. Collections for this study occurred in Victoria during 1991-1993, in New South Wales and the Australian Capital Territory during February 1992 and July 1993, in Queensland during August 1993, in Tasmania during September 1993, in Western Australia during October 1992 and October 1993. A sample of adults were stored in alcohol for description. If adults were absent, the juveniles were raised to adulthood in the laboratory. Specimens examined are lodged in the following collections: the Australian Museum (AM), Australian National Insect collection (ANIC), Barbara York Main personal collection, Zoology Department, University of Western Australia (BYM), National Museum of Victoria (NMV), Queensland Museum (QM), Tasmanian Museum and Art Gallery (TMAG), Western Australian Museum (WAM). Most of the material was collected by myself, and the abbreviation TAE was used in the lists of para types.