PROC. ENTOMOL. SOC. WASH. 94(2), 1992, pp. 253-262 ETHOLOGY OF NEOARATUS ABLUDO DANIELS (DIPTERA: ASILIDAE) IN SOUTH AUSTRALIA, WITH NOTES ON A^. PELAGO (WALKER) AND A^. RUFI VENTRIS (MACQUARTy R. J. Lavigne Entomology Section, Plant, Soil and Insect Sciences Department, University of Wyo-ming, Box 3354, University Station, Laramie, Wyoming 82071. Abstract.— The predatory and mating behaviors of Neoamtus abludo Daniels were stud-ied in paddocks south of Aldinga, SA. Although prey taken by A^. abludo represented five insect orders, 62.5% of the prey were honey bees. The majority of matings, in the tail-to-tail position, took place in the afternoon. Incidental data are included on the distribution and behavior of Neoaratus pelago and A^. rufiventris. Key Words: Diptera, Asilidae, Neoaratus abludo, predatory behavior, mating, Neoaratus pelago, Neoaratus rufiventris The present paper is the fourth in a series dealing with the behavior of South Austra-lian robber flies. Previous papers dealt with Neoitamus vittipes (Macquart) (Lavigne 1982a), Neoscleropogon elongatus (Mac-quart) (Lavigne 1982b), and Neocerdistus acutangulatus (Macquart) (Lavigne 1984). In the first paper, definitions of asilid flight terminology were presented and therefore need not be repeated here. While on sabbatical at the Waite Agri-cultural Research Institute (November 1978-May 1979), the author and his wife encountered a population of an undescribed species of Neoaratus, 8.5 km south of Al-dinga, SA. The species, Neoaratus abludo, was subsequently described by Daniels (1983). The population of N. abludo inhabited three hillside paddocks dominated by Ar-ena barbata Pott ex Link, intermixed with Echium plantagineum L. (Salvation Jane), Hypocheoris radieata L., and Scabiosa atro-' Published with the approval of the Director, Wy-oming Agricultural Experiment Station as Journal Ar-ticle No. J A 1650. purpurea L. (Fig. 1). The paddocks con-tained occasional trees, Ficus macrophylla Desj., Albizzia lophantha (Willd.) Benth. and Acacia pycnantha Benth., which had at one time received irrigation. A deep swale lined with Pinus halepensis Mill. (Aleppo pine) separated two of the paddocks. Within the swale were several additional flowering plants attractive to bees and wasps, Cirsium vulgare (Savi) Ten., Convolvulus erubescens (Willd.) Benth., Carthamus lanatus L. and Sonchus olevaceus L. At the west end of one paddock there was a stand of Eucalyptus trees within the eastern edge of which stood a row of 12 honey bee hives. N. abludo was studied by the author and his wife during the period January 5 to 23, 1979 at this site. It was estimated that the asilid population contained approximately 150 individuals. Because so little is known about the be-haviors of members of the genus Neoaratus, notes on the behaviors of two additional species, A^. pelago (Walker) and N. rufiven-tris (Macquart) have been included in this paper.