A total of 38 species belonging to 26 genera of Eumeninae are recorded from Hong Kong, among which two new species, namely Allorhynchium radiatumsp. nov. and Orientalicesa nigrasp. nov. are described and illustrated. Symmorphus tsushimanus Yamane, 1990 is newly recorded from China and its female is firstly described. Eighteen species are newly recorded for Hong Kong. Antepipona ferruginea Kim & Yamane, 2003 is synonymized with Antepipona rufescens (Smith, 1857) (syn. nov.) and Eumenes quadratus obsoletus Dover, 1926 is synonymised with Eumenes quadratus quadratus Smith, 1852 (syn. nov.). A checklist, a key and illustrations to Hong Kong Eumeninae are also provided.

We provide keys, descriptions and illustrations for 16 species of Scoliidae Latreille, 1802 found in Hong Kong, of which nine are new records for the territory, one is new to China and one is new to science: Scolia pakshaoensis sp. nov. The status of one species (Megacampsomeris sp. 1) remains uncertain; it may represent an additional new species.

A checklist of 23 species of Dryinidae and one species of Sclerogibbidae from Hong Kong is presented for the first time. Five subfamilies and seven genera of Dryinidae and one genus of Sclerogibbidae are recorded: eight species of Anteon; five species of Dryinus (belonging to groups 1 and 3); four species of Gonatopus (belonging to groups 1, 2, 4 and 7); two species of Aphelopus and Thaumatodryinus and one species each for Echthrodelphax, Neodryinus and Sclerogibba. Sixteen species are newly recorded from Hong Kong and three from China. Their geographical distribution are reported and illustrations of collected specimens are provided.

Field observations and rearing observations of five nests of Macromerella honesta (Smith) and four nests of Auplopus sp. were carried out in Hong Kong, China, in 2006China, in , 2009China, in , 2011China, in and 2012 Nests of Macromerella honesta were composed of two rows of exposed ovoid mud cells, affixed to broad leafs while nests of Auplopus sp. were constructed as variable masses of mortar affixed to a linear substrate (thorns, wire-mesh, etc.). Cells of the nests of Auplopus sp. were more or less cylindrical and covered with a layer of hardened mud finished with a plant gum coating. Both species used a single dismembered spider, transported ventrally to the nesting site, for cell provisioning. Active guarding was observed at all nesting sites. Overlap of generation was also recorded with active nest cooperation (construction and prey provisioning) between individuals of different generations on the same nesting site. The two species were inferred to be at least bivoltine in Hong Kong.

The taxonomic limits of Palpostilpnus Aubert, 1961 are reviewed. The genus is characterized mainly by having a very elongated maxillary palp; head short and depressed, with mandible small and with distinct basal groove; ovipositor short and slender, needle-like. A total of seventeen species are recognized, of which ten are described as new: P. aki sp. nov., P. angka sp. nov., P. angkor sp. nov., P. hainanensis sp. nov., P. mangrovi sp. nov., P. pterodactylus sp. nov., P. ranui sp. nov., P. singaporensis sp. nov., P. tamasek sp. nov. and P. trifolium sp. nov. The combination Palpostilpnus rufinator (Aubert, 1961) stat. rev. is proposed. An illustrated key to the known species of the genus is provided.