Bluetongue was introduced into northern Europe in 2006, and members of the Obsoletus group of Culicoides biting midges were implicated as vectors of the disease. Identification of two of the four members of this group is considered difficult, if not impossible, when undertaken morphologically. Previous studies have attempted to determine morphological techniques to differentiate these species, yet have nor investigated the effect of seasonally, or geographical location on midge morphology. Here, midges were collected from two sampling locations the UK, France and Spain. Morphometric measurements were compared between the start, middle and end of the vector. While both geographical and seasonal variation in midge morphology was identified, identification techniques, based on the morphology of the abdomen, were also determined.