I sent this message directly to the museum specialists a few weeks ago, but have not received a reply, so turn to the readers of the forum - I have quite an odd question for you, if you have a moment!
I'm working on a book based on medieval British legends of strange otherworldly peoples. In one of the texts I’m translating (Lludd a Llefelys) there’s a story about a strange race of creatures (the Coranieid) who come to Britain and oppress the kingdom until they are all killed by Lludd, the king and the hero of the story. The way Lludd does this is very strange – he crushes some ‘pruet’ (in this context the word probably means bugs, grubs or insects) in water, and he splashes the resultant mixture on the heads of all his citizens. The British are fine, but the strange race of creatures are all killed by contact with the mixture.
The book is taking a slightly tongue-in-cheek view of these events and taking them all literally, so I wondered if you could suggest any animals which give off chemicals when crushed/bruised/mashed? Preferably the chemicals would be ones more dangerous to other animals than humans. The story makes it clear that the critters were crushed either while alive or directly after death (sorry if you’re squeamish). Also it’s possible that they are supposed to be either more common in France than in Britain, or not present in Britain at all. Can you think of any insects like this?
One type of insect I thought of straight away are shield/leaf bugs. Although they seem relatively common I had heard their horrible defensive odour contained cyanide, which I imagined would only be produced whilst they were alive, and could easily be extracted by crushing them. Having looked it up though, I can’t seem to find out whether British/French versions have cyanide. Does anybody here know?