The family Pteromalidae is one of the largest and taxonomically difficult families of Chalcidoidea (Hymenoptera) to deal with. They are distributed in all biogeographical areas of the world and show great diversity in their morphological and biological characteristics. Majority of Pteromalidae are primary or secondary parasitoids attacking a large range of insect hosts in their various stages of development, hence of economic importance in the biological control of noxious insect pests. A few pteromalids are also phytophagous developing in seeds of plants, some make galls in plants and still others develop as inquilines in galls caused by other insects.
The family comprises over 3000 described species under 552 genera globally (Boucek & Heydon, 1997). As regards India and adjacent countries the number is too small. Though there were several scattered publications on the systematics of Pteromalidae of India and adjacent countries, it was Boucek et al. (1979), who provided a complete picture of the then fauna of the region. They recorded a total of 112 species of Pteromalidae under 80 genera. Later Farooqi and Subba Rao (1985, 1986) keyed out and catalogued 90 species of Pteromalidae under 78 genera from India and adjacent countries. Several new genera and species have been subsequently described under the family from the region (Ahmad, 1995, 1997, 1998, Ahmad & Agarwal, 1994 a,b, c, Sureshan, 1999, 2000, 2001 a, b, c, Sureshan & Narendran, 1995, 1998, 2000 a, b, Narendran & Mini, 1998). Recently Sureshan (2003), made a comprehensive revision of the subfamily Pteromalinae of the Indian subcontinent which included 131 species under 57 genera. Sureshan & Narendran (2003) have also compiled a checklist of the Pteromalidae recorded from the Indian subcontinent. The checklist deals with altogether 96 genera and 198 species. Subsequently Gibson (2003) synonymised Riekisura keralensis Narendran under Soleneura, thus reducing the number of genera known from the region to 95.
In order to facilitate the identification of 95 genera of Pteromalidae currently known from the region an updated key to genera is provided here. Sphegigastrella Masi, genus of the subfamily Pteromalinae as recorded by earlier authors is not included in the present key because of the suspicion of the validity of the taxon. The genus originally belongs to the African region and an indetermined species of it was recorded from the Indian subcontinent (Boucek et al. 1979). The geographical area covered by the key broadly includes the countries viz. India, Pakistan, Nepal, Bangladesh, Myanmar and Sri Lanka covering the Indian subcontinent. According to Boucek et al. (1979) pteromalid fauna of this region is not isolated from the rest of the world. Recent studies proved that many Palearctic and circumtropical genera and species are represented here.