Taxonomic studies on parasitic Hymenoptera were mainly based on comparative morphology of adult wasps and occasionally on molecular surveys. Nowadays, wing interference patterns (WIPs) are applied to separate cryptic species of microhymenoptera. In our current research, colour characters of WIPs are quantified as wing interference colours (WICs), for the first time. In this regard, we demonstrated that statistical analysis of WICs is able to perform as well as side-by-side comparison of WIPs. WICs is a new concept including three main wing colours and their qualitative attributes. WICs of five Eurytoma species (Hymenoptera: Chalcidoidea, Eurytomidae), E. acroptilae Zerova, E. amygdali (Enderlein), E. caninae Lotfalizadeh and Delvare, E. plotnikovi Nikols’kaya and E. rosae Nees were analysed, for the first time. For this purpose, six colour parameters including red, green and blue (RGB) as well as hue, saturation and value (HSV) were compared. WICs alone could differentiate Eurytoma species. Geographic variation and sex determination were also examined based on WICs. Since these characters were similar and unique in both sexes, they were very useful for linking conspecific males and females. The study of different populations of the same species confirmed the stability of WICs.