What is the meaning of Bluebottle?

Any of various blowflies of the genus Calliphora that have an iridescent metallic-blue body and make a loud buzzing noise when flying.

A marine jellyfish of the genus Physalia, which includes Physalia physalis, the Portuguese man-of-war, and Physalia utriculus, the Pacific man-of-war; a man-of-war.

A cornflower, a plant that grows in grain fields, Centaurea cyanus, with blue flowers resembling bottles.

A blue ant, Diamma bicolor, a parasitic wasp native to Australia.

Any of various large papilionid butterflies of the genus Graphium, also called triangles, etc.

A police officer.

Source: wiktionary.org