I made a rare observation (for me) of a yellow moth the other day and one thought led to another, as it usually does…
But first the moth. I was arriving home when I saw what looked like a white cherry-blossom petal on the breeze, then I realised it was pale yellow, so I thought of a brimstone yellow butterfly, not common in these western parts. But it was too small and when it landed on a leaf I realised it was a moth, in broad daylight. Luckily I had my camera in my bag.
It didn’t take long to Google “yellow moth” and identify the one I had seen. It’s Opisthograptis luteolata, whose common name is brimstone moth. Brimstone means sulphur (sulfur to the Americans), but we’ll come to that in a minute.
I haven’t seen it explained anywhere, so I am guessing about the origins of the scientific name. The similar word opisthography comes from the Greek, meaning “behind writing”, or writing on the back of something. Perhaps because of the wing markings?
I worked out for myself a more fanciful explanation based on the shape of the moth’s caterpillar. Another similar word, Opisthotonos, is an extreme arching of the back or neck, caused by a spasm. And look at the caterpillar…
I was also thrown by the end of the scientific name for the moth being graptis and not graphis. Grappa (as in the name of the Italian brandy) means “grape stalk”. So I ended up translating Opisthograptis as “arched twig”. Presumably I am wrong.
The luteolata part of the species name is easy, as luteus is Latin for “yellow”. I know this as I have an old yellow deciduous azalea in a pot with the name Rhododendron luteum. It is currently in bloom.
Then there is the brimstone butterfly, scientific name Gonepteryx rhamni. The second part is again easy, as Rhamnus is the scientific name for buckthorn, a shrub on which the butterfly lays its eggs, so that the plain green caterpillars can eat the leaves.
As for Gonepteryx , the pteryx part means “wing” in Greek, as in pterodactyl. The Gone bit is as in “gonads”, from the Greek gonos, meaning “procreation”. Does the name come from the fact that the butterflies have an elaborate mating dance on the wing before landing and breeding?
By the way, the upperside of the male is yellow and the female green, but they always rest with their wings closed and from the underside they are very similar, although the female is slightly paler.
Both the brimstone butterfly and moth are named after their colour, brimstone being an old word for sulphur/sulfur, and we all know that’s yellow.
The word brimstone comes from the Old English, brynstan, from bryne “burning” and stan “stone”. Perhaps this is because it is found in hot places? Certainly the phrase “fire and brimstone” has come into popular usage for a form of Christian preaching threatening hell and damnation for sinners. Do we think that hell is on the flanks of a volcano?
The word sulphur is a very old Latin one for the substance, with variations sulfur and sulpur. The spelling has a long and complicated history you can read about here. In the 19th century when Britain plumped for the ph spelling America decided on the f word. I think the Canadians still use both versions and our British Royal Society of Chemistry was persuaded in 1992 to use “sulfur”, so I suppose that now leaves us here with both spellings, too.
Even older is the Greek word for sulphur, theion. Variations of this are found only in partnership in scientific terms, such as in the chemical thiocyanate.
Thio is not to be confused with theo, as in theobromine, an alkaloid found in chocolate. That has nothing to do with sulphur (nor bromine) and comes from the Greek theo (god) and broma (food), Theobroma being the scientific name for the cocoa genus of plants. Chocolate is of course the food of the gods!
For the record, the name of the smelly gas bromine is not from that word for food, but from the Greek word bromos, meaning “stink”.
Finally, a pretty picture…
By the way, if you want to find out more about moths from a dedicated follower of winged things, I suggest popping over for a look at the Countryside Tales blog.