Strange are the destinations, sometimes, of "a mind forever voyaging through strange seas of thought, alone". Here in Germany, for example, I find that Noel Coward comes to mind a lot.
Driving over miles and miles of level countryside, it is hard not to think of the cryptic comment of the character in Private Lives who states the obvious: "Very flat, Norfolk!". And "Let's not be beastly to the Germans," becomes a frequent mantra of self-restraint in the face of the idiosyncrasies of one's Teutonic neighbours.
The mind rolls on, and you recall that just as Joyce had his Martello Tower in Sandycove, and Maugham the "Villa Mauresque" at Cap Ferrat, so too had Noel Coward a Jamaican house called "Firefly", where he was buried when he died in 1973. And that, of course, leads on to thinking about real fireflies.
The firefly, as it happens, is not a fly at all, but a member of the beetle family Lampyridae. It is a close cousin of the English glow-worm, but a creature, by and large, of the lower latitudes that emits a characteristic flashing light, intended to attract a mate. Some of the larger tropical species flash so brilliantly at night that it is possible to read a newspaper by their light, and in days gone by it was common for a number of them to be kept in a cage to serve as a heatless domestic lamp.
As might be expected, the behaviour of the firefly has found its place in folklore. In parts of India, for example, they were believed to have their origins in the sparks escaping from a fire, while in other cultures they were thought to be the eyes of gods that had fallen in fierce battles long ago.
The firefly's light is produced by organs arranged along the two last segments of beetle's body. The organs contain cells that store a compound known as luciferin, named after the fallen angel Lucifer, the quondam carrier of light.
Surrounding the cells are tubes that can be opened to allow air to enter, and oxygen passing through the tubes reacts with the luciferin to produce the characteristic "cold" light. The whole ensemble is cleverly provided with reflectors to direct the illumination outwards, the on-off sequence of flashes being controlled by the insect's regulation of the oxygen supply.
The firefly's flash is commonly a shade of green, but some species emit yellow light, or blue, and at least one can flash in red. Like lighthouses, the different species flash with a unique pattern which allows the individual insect to identify potential partners without embarrassing, or even dangerous, confusion.