This huge and utterly magnificent butterfly is not uncommon in southern France, but rarely seen in numbers, and in fact I cannot remember seeing more than one or two at any one time. Because it is so large, it is almost unmissable. In England the subspecies is britannicus (the European subspecies is gorganus) which has a paler yellow colour and darker marginal regions, and is confined to a small area of the Norfolk Broads, but in France it is distributed over a wide variety of terrain including mountainous areas and its larval hostplant requirements are quite different.

It is often quite hard to photograph as its wings are constantly moving even when it is nectaring, possibly because it is a (comparatively) heavy butterfly, and needs to keep the wingbeats high to assist buoyancy.

I particularly like the "shower" of blue cells in the uph black band, reminiscent of a firework display or a comet.

The only butterfly it could be confused with is the inaptly-named Scarce Swallowtail (Iphiclides podalirius), or if you are very lucky, the very scarce (now this one is scarce) Southern Swallowtail (P. alexanor).

observations

a male, puddling.

a male, taking salts. I rather like the three Southern Small Whites (Pieris mannii) which seem to be lined up and staying a respectful distance behind the "king".

this shows the width and wing area of this magnificent butterfly. It's a pity that the right hand tail is missing, but this is probably an effective defence measure, as it was probably lost to a predator who thought it was attacking the vulnerable head end of the insect.

a male, puddling for salts. One of the few occasions it stays still and open enough for a decent photograph opportunity.

photographed on the move, as it was nectaring.

a mating pair. The first time I have ever seen this, and quite probably the last.

a male puddling in company with another machaon and many other species.

this was acting in a very un-swallowtail-like way, to my eyes. It was circling around the bush, returning to the same perch (the top-most point on the bush, about 2.5m high) each time, as if guarding its territory. It did facilitate a shot of the underside, even if from a distance of about one metre (I have blown up the photograph for detail). It was a fabulous fresh specimen, with very light and delicate markings, that may have just emerged.

a larva, feeding on Fennel (Foeniculum vulgare), I believe.

an ovum, laid on a plant that I don't think is Fennel, the normal larval hostplant and quite common in Var. Machaon does have a wide variety of larval hostplants, and I think the plant in 15588 is probably related to Fennel. Any advice would be welcome.