Females are easily recognised by the following combination of characters:
- mid tarsi 4-segmented
- fore-wing uniformly hairy - without any evident bare patches
- body with head and mesosoma (thorax) black, metasoma (abdomen) bright yellow
E. formosa’s DNA has been sequenced for several different gene fragments, and these can be found on the Nucleotide, alphabet of life website
with the following accession numbers: Mitochondrial: CO1: AY264337; Ribosomal:18S: AY918985; 5.8S and ITS1: AY615783; 28S: AY615760.Polaszek et al (1992) included E. formosa in the complex of parasitoid wasps that attack the whitefly pest Bemisia tabaci. Because of its more or less cosmopolitan distribution, E. formosa is included in identification keys to Encarsia species from Australia (Schmidt and Polaszek, 2007); China (Huang and Polaszek, 1998); Egypt (Polaszek et al 1999); Mexico (Myartseva and Evans, 2007) and U.S.A. (Schauff et al, 1996).Synonym: Trichaporus formosus (Gahan).