The eggs are very similar to those of Rapæ, resembling ribbed and striated sugar loaves; and the larvæ are of the same rich glaucous green, but may be identified by the black spiracles surrounded by yellow rings. In our gardens we may find both eggs and larvæ on mignonette and horse-radish; the other food plants of this species include the water-cress (Nasturtium officinale), winter cress (Barbarea vulgaris), rape (Brassica Napus), cuckoo-flower (Cardamine pratensis), and Jack-by-the-hedge (Sisymbrium Alliaria).
The pupa is greenish, and marked with small black dots.
The Bath or Green-chequered White (P. Daplidice)
There is no doubt that many butterflies migrate from one country to another across the seas; and as the Bath White is very common on the other side of the Channel, and has been taken very sparingly in England almost exclusively in the south-east, it is highly probable that the majority of those that have been captured here are specimens that have taken a voluntary trip across the water, or have been blown over during rough weather.
This butterfly is one of our greatest rarities, and the capture of a specimen in England is an event that must necessarily be recorded in our entomological literature. It seems that Daplidice has bred in England, for its caterpillars have been found at large on one or two occasions, so I will give a short description of the various stages of the insect, with a hope that some of my readers may be fortunate enough to meet with it.
The female butterfly is shown on [Plate I], fig. 6. From this it will be observed that each of the fore wings is tipped with a rather large smoky-black blotch, in which are four white spots. A double spot of the same colour also occupies a place near the centre of the wing, and another smaller and round one lies near the anal angle. The hind wings are clouded with grey, and bordered along the hind margin with distinct smoky-black spots.
The male may be distinguished from the female by the absence of the spot near the anal angle of the fore wings, and of all the clouds and spots of the hind wings. Nevertheless the latter have a decidedly clouded appearance, but this is due to the markings of the under surface showing through them.
