Nick Upton / Gall fly / Greater fruit fly (Terellia longicauda) pair resting on the unopened flowerhead of a Woolly thistle (Cirsium eriophorum), the host plant for its larvae, in chalk grassland meadow, Wiltshire...

Nick Upton / Gall fly / Greater fruit fly (Terellia longicauda) female resting on the tip of a Woolly thistle (Cirsium eriophorum) leaf, the host plant for its larvae, in chalk grassland meadow, Wiltshire, England...

Nick Upton / Gall fly / Greater fruit fly (Terellia longicauda) pair, with male turning its abdomen towards the female and inflating a pouch to release courtship pheromones, on the leaf of a Woolly thistle (Cirsiu...