This May Be The Most Astounding Story I’ve Heard About The Development Of The Citroën 2CV And It Involves Literally Using Fireflies As Lights

This past week I was up in Detroit with David, working on Important Autopian Things, and we decided to inspect the thriving local car culture by showing up to a Cars and Coffee meetup. Of course, we were really late (why the hell do these all have to start so damn early?) but we did get to see a few wonderful cars, and, almost as excitingly, people. One of these people was a French automotive engineer named Aurel, and he told me one of the most incredible, charming, and so so very strange things about the development of the Citroen 2CV that I’ve ever heard.

If you’re unfamiliar with the 2CV, that’s a terrible condition to be in, so let’s solve your problem really quick. Here, I made a whole video about the 2CV a few years back:

The basics are that the 2CV was designed to put France’s rural farmer population on motorized wheels, and off of cranky, slow (probably drunk) French horses. The project came to be when Pierre-Jules Boulanger, the man in charge of Citroën’s engineering and design departments after they were bought by Michelin in 1935, found himself stuck behind a farmer’s slow horse and cart.

This made Boulanger realize there needed to be a car for the peasants, something to replace the archaic horse carts, which is when Boulanger came up with his dream peasants’ car, not in the form of drawings or technical specs, but a set of requirements.

The fundamental requirements for the 2CV (also called the Deux Chevaux, or — in its early prototype stages — the TPV for “Trés Peitite Voiture,” or Very Small Car) were set in 1935 and were as follows:

The car should carry two farmers wearing clogs, 50 kg of potatoes or a keg, at a maximum speed of 60 kph with a target MPG of 78 (3 l/100km). Comfort would be key so eggs don’t break driving through fields and bumpy roads.

Also, it had to be dirt cheap, rugged, and simple to maintain and repair. The war paused the development of the TPV (though Boulanger did use the occupation period in France to do some really brilliant sabotage of the Nazi war effort) and then picked up again after the war, but with a slightly less austere (but not that much less) design.

From these humble origins it grew into France’s people’s car, for city and country people. It stayed in production from the end of WWII to 1990.

Okay, back to my interaction with Aurel.

I was asking Aurel about what seems to be one of the greatest examples of cheapskatery in all of motoring: Citroën 2CV Fourgonette vans using a split license plate so they’d only need one tiny little light bulb to illuminate it (from the middle out, with two windows on the light instead of one) instead of two lights illuminating from either side.

While this bonkers split-plate business is interesting, it can’t even hold a candle – or, in this case, a firefly – to what Aurel told me next: He once read that, in an attempt to eliminate the need for a battery on the car that would become the 2CV, there was some early experimenting with position and other running lights (you know, side lights, taillights, that sort of thing — but not headlights) that used actual, living fireflies and glow worms.

I, of course, was absolutely thrilled and hooked at this astounding example of some of the most Flinstones-sounding shit I’ve ever heard come out of France, or, really, anywhere. Glowing insects used as automotive lighting? Incredible! I seized Aurel by the shirt and, my eyes forming twin spirals of madness, demanded to know more, more, more.

Aurel came through!

The original source Aurel found back in 2008 was no longer online, but he had the foresight to save the fascinating text, which I couldn’t find on the Internet Archive, even, probably because I don’t have the original French. Here’s Aurel’s translation:

Alongside engineers, Boulanger offers opportunities and resources to scholars and experts whom only report to him.

 

Frifshof (is it really a name ?) Lecoultre is Swiss and a doppelganger of Professor Calculus. He was first an astronomer at the Geneva Observatory before he moved to Paris and then joined Citroën. He is the man behind the glow-worms and fireflies. He raises and observes them to understand the way they “work”. Maybe he could use them for the TPV as Boulanger does not want to use a battery but regulation requires some lights. He also researched manta ray’s bones which turn luminescent when decaying. Similarly, he tried to develop a glowing paint to cover the fenders.

Wow. Just, just, wow. Glow worms and fireflies and glowing manta ray bones (do they even really have bones?) were considered by Boulanger himself. Thankfully, there is at least one confirmation of this story online:

For months, Pierre Boulanger tamed fireflies and lampyres to try to understand how they worked and see if it could be used on the TPV , instead of electricity . To balance the impulses of these brains, the laboratory, directed by Maurice Pompon, tests their findings and technical methods . Often Boulanger wants to find out for himself . He tries the models and with each evolution of the car, he wants to drive it in person. Thus are developed all sorts of surprising solutions : 1 oilcloth bodywork or even with phosphorescent wings.

The prototype being discussed in this part is a very early TPV prototype known as the Terrasson Prototype. This reference supports much of what Aurel found all those years ago: the attempt to replace electric lights with bioluminescent ones, attempts at training the insects (to, what, blink for a turn?), and the glowing fenders (called “phosphorescent wings,” using the British term) in that text.

Pictures of the Terrason prototype show an incredibly radical and brilliant car from Boulanger’s designs, but they feature a lone cyclopean electric light instead of a jar of fireflies, sadly.

Aurel suggested that the insect lights would likely have been for marker and position lights and taillights, with a dynamo-driven electric lamp for the headlight, anyway, since you can’t really expect all that much light from a bunch of glow worms.

I just can’t get the idea out of my head; using fireflies as lights feels like something out of a charming old storybook, a fable about the time the faeries and gnomes worked together to build cars for all the Good Farmers of France, if they would, in turn, provide magic millet for their queen, or something.

So far these are the only two references I’ve found, but I’d like to consider this article just the beginning; if there’s some sort of photo out there of a TPV with a jar of fireflies or glow worms mounted on the rear bumper, shining through a red lens to act as a taillight, I want to see it.

Badly.

So, if anyone knows anything or has even heard of this at all, please let me know! I’ll see if I can get ahold of Citroën’s archive department, too. It’s just too good to leave alone.