J. HYM. RES. Vol. 6, 1997, pp. 75-91 Update on the Flower Associations of Southern African Masarinae with Notes on the Nesting of Masarina stntcki Gess and Celonites gariepensis Gess (Hymenoptera: Vespidae: Masarinae) Sarah K. Gess, Friedrich W. Gess, and Robert W. Gess Albany Museum, Grahamstown, South Africa Abstract. — Flower visiting records are presented for seven newly described species of Masarinae from the Richtersveld and for Masarina strucki Gess. The potential of these wasps as pollinators is discussed. Celonites gariepensis Gess and Masarina peliostoini Gess are associated with Peliostomum and the former, at least, with Aptosimum (Scrophulariaceae), a preference shared with four other species of Celonites. Masarina ti/lecodoni Gess appears to be restricted to Tylecodon hallii (Tolken) Tolken (Crassulaceae) and is apparently the first recorded insect visitor to a Ti/lecodon species. Jugurtia codoni Gess is an abundant visitor to Codon royenii L. of the family Hydrophyllaceae, one of the preferred forage plant families of the North American masarines but otherwise not known to be visited by masarines. Records for Masarina strucki from a wide range of localities confirm its, for a masarine, unusual association with Herniannia spp. (Sterculiaceae). In the Richtersveld Zygophyllum spp. (Zygophyllaceae) were being visited, though not apparently favoured, by Cer-aniius brevitarsis Gess, two species oi Jugurtia, J. codoni Gess and /. koeroegabensis Gess, and Masarina tni.xtoides Gess. These records are of interest as Zygophyllum has only otherwise been shown to attract one other species of Masarinae, a Quartimoides species, in the Central Namib Desert. Some aspects of the nesting of C. gariepensis, which constructs aerial mud cells, and of M. strucki, which nests in the ground, are presented and discussed. Gess (S.K. 1996) presented a synthesis of the available data on the nesting and flow-er visiting of the Masarinae in southern Africa. Recent fieldwork in southwestern southern Africa, most notably in the pre-viously under collected Richtersveld Na-tional Park in the extreme north of Na-maqualand (Fig. 1) (16-24.ix.l995 and 5-18. ix. 1996), has resulted in the discovery of new species, additional flower associa-tions of particular interest, and a nest each of Masarina strucki Gess and Celoiites gar-iepensis Gess. Descriptions of the new spe-cies are given in Gess (F.W. 1997) and the flower visiting and nesting data are pre-sented and discussed in the present paper. Some other masarines collected in the Richtersveld National Park, all extending the known distributions for the species, are: Ceramius cerceriformis Saussure, four species of Jugurtia, j. braunsi (Schulthess), /. braunsiella (Schulthess), /. calcarata Rich-ards, and /. duplicata Richards, two species of Celonites, C. ch/peatus Richards and C. pcliostomi Gess. Flower visiting records for these species of Jugurtia and Celonites con-firm previously recorded flower family choices (Gess, S.K. 1996). Celonites Latreille Celonites gariepensis Gess Distribution. — Celonites gariepensis Gess has been recorded from only the Richters-veld National Park in northern Namaqua-land (Gess, F.W. 1997). Floioer visiting. — On the Koeroegabvlak-te (28.11S, 17.03E) (Figs. 2-5) C. gariepensis females and males were foraging only on flowers of a species of Peliostomum (Scrophulariaceae), together with Celonites ch/peatus Brauns, Celonites pcliostomi Gess (Fig. 6) and Masarina pcliostomi Gess (Fig.