This piece was inspired by a passage in chapter 21 of Bram Stoker's Dracula. Count Dracula manipulates Renfield, a mentally ill entomophagist, by sending enticing insects in through the window:
"...He used to send in the flies when the sun was shining. Great big fat ones with steel and sapphire on their wings; and big moths, in the night, with skull and cross-bones on their backs."
Dr. Van Helsing, who is listening to Renfield's tale, nods and adds, "The Acherontia atropos of the Sphinges - what you call the 'Death's-head moth'!"
And then nothing else is said on the matter. But I found the idea of a "Death's-head moth" intriguing, so I looked it up. Apparently there are three different known "death moths." Two of them are known only in parts of Asia but there is one occasionally found in Europe, which mine is based on.
There seem to be various legends about them. Some say that if you see one it means that you will die, or someone you know will die. Others say that if you see one on someone's house it means someone who lives there will die, etc. The only way to prevent the death is to catch the death moth and kill it, which I think is awful. The poor little things can't help it if they're gloomy omens of doom!
I suggest you Google image search these guys. In some cases the skull on their backs is really uncanny!