A book I’m reading mentioned bluebottles and greenbottles in the same sentence, in a way that presumed that I would know the difference between these types of insects, and I realized I hadn’t a clue about bottles of any color. “Daggurnit, he doesn’t know his bluebottles from his greenbottles!” is what some hay-chewing old man might say about me in mockery of my citified, bug- and bottle-ignorant ways. Personally, I’d rather not be mocked, so I looked it up. It turns out both colors of bottles are the same bug, which is neither bottle-like in any observable way nor is it generally all blue or all green. It looks like this:
(Apparently opalescentbottle was a mouthful.)
The same bug is also known by the name blowfly, which I’d heard without ever understanding. But in the same way that bluebottle seems like an arbitrary name for this creature, blowflies don’t actually blow on anything. They got that name, apparently, from an Early Modern English term flyblown, which describes meat — animal and otherwise, butchered and living — that has been contaminated with fly eggs. In fact, there’s even a word flyblow that describes the eggs themselves. Citing a Texas A&M textbook, Wikipedia notes that the first recorded instances of the word blow being used with flies themselves — as opposed to the eggs, I guess? — are Love’s Labour’s Lost, The Tempest and Antony and Cleopatra. So, you see, even the lowly fly can benefit from William Shakespeare’s verbal magic.
Blowfish, on the other hand, got their name as a result of their fondness for recreational oral sex. (Research ongoing. Will update with proper sourcing shortly.)