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Greenbottle Lucilia sp

There are many species of green or copper-like flies called Greenbottle in common English. In gardens two species are predominant: Phaenicia sericata and Lucilia caesar. In the field and from pictures it is virtually impossible to tell these two species apart. And there are more similar species in the genus Lucilia. Lucilia bufonivora for instance. This is not a pleasant fly, for it deposits its eggs in the nose of a toad. The toad is than eaten from within. Another Greenbottle is Lucilia cuprina. The larvae are studied, for they excrete an liquid that is a strong antibacterial. Very famous is Lucilia sericata. The maggots of this species are used to treat dirty wounds. The maggots only eat dead flesh and leave the living flesh alone. On the other hand the maggots cause Fly Strike in sheep. And there are more Lucilia species. All are looking like THE Greenbottle, so actually there is no species you may call THE greenbottle.

And that is not all. There are also some green house flies, also almost identical to the Greenbottles from the Lucilia genus. These include Neomyia cornicina and Neomyia viridescens. Their maggots do not live in flesh, but in cow dung. You can tell them apart by looking at the angle of the big vein in the wing. It's curve is more rounded than that of the Lucilia species. Neomyia viridescens can be told apart from Neomyia cornicina, for the part just above and between the eyes is green as well. In other species this part is either black or silvry grey. All differences are extremely subtle though. And yes, there also is a green parasitic fly called Gymnocheta viridis. This one however can be told apart from all others, for it has a more elongated shape and it is covered in much longer, thicker and blacker hairs.

On many websites a Greenbottle is simply called Lucilia caesar. In many cases however, it is one of the other green species. This is often due to the fact that in most insect guides and field guides only Lucilia caesar is mentioned. Many people therefor think it is Lucilia caesar they see. But chances are they actually see another species, some of which are just as common as Lucilia caesar.