The swallow-tailed butterfly is found plentifully in the fens of Cambridgeshire, and Norfolk and Suffolk, and very commonly in the environs of Paris. It is seen from the beginning of May till towards the middle of June; then from the end of July till September. It frequents gardens, woods, and, above all, fields of lucerne. It is easily taken when settled, particularly at sunset. This is one of the largest and the most beautiful of the European butterflies. The wings are variegated with yellow and black; the eyes, antennæ, and trunk are black. The body is yellow on the sides and underneath, and black above. The front wings have rounded edges; the hind ones, on the contrary, are notched, and one of these notches is prolonged into a sort of tail. The first are black, spotted and striped with yellow; the second have their upper part and middle yellow, with some touches only of black. Near the margin is a broad black band, dusted with blue; lastly, six yellow spots in the form of a crescent run along the border, and end in a magnificent eye of a reddish colour, bordered with blue. [Illustration: Fig. 141.--Papilio Alexanor.] The caterpillar of this species is large, smooth, and of a beautiful light green, with a transverse black band on each ring. These bands are sprinkled with orange spots. It lives on the fennel, carrot, and other Umbelliferæ. If teased, it thrusts from the first ring after the head a fleshy, orange-coloured tentacle. The chrysalis, attached to a stalk of grass, is sometimes light green, sometimes greyish. In the low Alps, on the plains near the environs of Digne and Barcelonette, is found in the months of May and July the _Papilio Alexanor_ (Fig. 141), and in Corsica and Sardinia is found the _Papilio hospiton_, a rare species, nearly related to our swallow-tailed butterfly, but which we will here content ourselves with mentioning. [Illustration: Fig. 142.--The scarce Swallow-tailed Butterfly (_Papilio podalirius_).]