Opening a purse but only getting flies flying out usually means that the purse is empty in cartoons. Here the conversation suggested that frogs uses flies as currencies and thus subverts the convention.
Another layer on top is that two flies are required, but the customer only got one, so they’re still broke, just like the conventional representation of being broke.
Technically the insect in the original gag was a moth, not a fly.
Certain kinds of moth caterpillars eat cloth. Banknotes at the time and location of the original gag were made of cotton fibre paper, (and indeed some places still do this, or did so very recently) so were theoretically as delicious to those caterpillars as cotton clothes would be.
For clothing, mothballs can be used to deter them from laying eggs wherever the clothes are, but it’s kind of hard to cram a mothball into a wallet. Also, the money probably already had the eggs on it, which is too late for a mothball anyway.
Thus, if a moth flies out of your wallet, it means that the paper money is long gone because that moth had time to get all the way from egg, through note-munching caterpillar to moth before you opened your wallet.
Opening a purse but only getting flies flying out usually means that the purse is empty in cartoons. Here the conversation suggested that frogs uses flies as currencies and thus subverts the convention.
Another layer on top is that two flies are required, but the customer only got one, so they’re still broke, just like the conventional representation of being broke.
Technically the insect in the original gag was a moth, not a fly.
Certain kinds of moth caterpillars eat cloth. Banknotes at the time and location of the original gag were made of cotton fibre paper, (and indeed some places still do this, or did so very recently) so were theoretically as delicious to those caterpillars as cotton clothes would be.
For clothing, mothballs can be used to deter them from laying eggs wherever the clothes are, but it’s kind of hard to cram a mothball into a wallet. Also, the money probably already had the eggs on it, which is too late for a mothball anyway.
Thus, if a moth flies out of your wallet, it means that the paper money is long gone because that moth had time to get all the way from egg, through note-munching caterpillar to moth before you opened your wallet.
Oh a moth makes sense! I hadn’t thought of that
…or maybe it means you have a light in your wallet.