Synonyms for Bluebottle (same or very similar meaning)
WordNet sense 1 (an annual Eurasian plant cultivated in North America having showy heads of blue or purple or pink or white flowers):
cornflower, bachelor's button, Centaurea cyanusWordNet sense 2 (blowfly with iridescent blue body; makes a loud buzzing noise in flight):
Calliphora vicinaFrom the ODE community, based on WordNetadd/edit