344 
PAPILIONIDAE 
away in search of more plants. Apparently one egg only 
is laid on each plant by the same female. Sometimes 
as many as five or six eggs may be found on the same 
leaf of a plant, usually all being of different ages, denoting 
that in all probability they have been laid by different females. 
The usual food plant is Hog’s Fennel (Peucedanum palustre), 
although Wild Angelica ( Angelica sylvestris) is sometimes 
selected. 
At Wicken Fen, Cambridge, on July ist, 1893, I found about 
three dozen eggs of P.machaon laid singly on theunder surface 
of the leaves of Hog’s Fennel, also some larvae in the first 
stage. Some of the eggs were recently laid, being of a pale 
yellow colour ; most of them hatched during the following 
seven or eight days. 
Egg. The egg is globular, with a smooth surface, and the 
base is flattened. It measures 0-90 mm. in height. When 
first laid the colour is pale yellow, and when a week old it is 
irregularly zoned or broadly blotched with warm coppery- 
brown. It finally changes to purplish-grey, with about a 
dozen longitudinal dark stripes. The egg stage lasts from 
eight to ten days according to temperature. 
Directly after hatching, the little larva eats a large portion 
of the egg-shell as its first meal. 
Larva. After feeding for thirty days, the larva becomes 
fully grown, when it measures about 41 mm. while resting 
and' about 52 mm. when crawling. The ground colour is a 
brilliant green, inclining to bluish along the lateral lobes and 
claspers. The segmental divisions are banded with purple- 
velvety-black ; these bands are widest on the dorsal surface, 
wavy in outline on the side and terminating in a fine line below 
the spiracles ; in the centre of each segment is a dorsal trans¬ 
verse velvety-black band, broken up into three portions, 
except along the posterior edge, by two deep orange spots 
and one at each end. On the first segment this band has no 
orange spots. Then follows an oblique black marking enclosing 
the whitish spiracle, and a shorter oblique sub-spiracular black 
mark. Between these tw T o black markings is a large deep 
orange spot; all the orange spots are nearly round. Along 
the lateral surface is a series of black-velvety spots, two on 
each of the sixth, seventh, eighth and ninth segments, one on the 
