_Edusa_ catching is very lively sport, and is likely to prove sufficient for any lover of outdoor exercise under a scorching sun; for this butterfly is not only very powerful on the wing, but its flights are usually long, so that a good run is often absolutely necessary in order to capture it. On very hilly ground, such as _Edusa_ loves, chase is often hopeless, and then it is necessary to resort to stratagem. In such a case the best plan is to make a very cautious approach when the insect has been observed to settle, and then secure it with a sudden down-stroke of the net. The eggs are laid during May and June by a few females that have survived the winter. The caterpillar may be found in June and July on its food plants, the chief of which are the bird's-foot trefoil (_Lotus corniculatus_), and the purple and Dutch clovers (_Trifolium pratense_ and _T. repens_). Its colour is grass-green, and it is marked with a narrow whitish stripe on each side, which is broken by the yellow of the spiracles. The chrysalis is of a pale yellowish green, and is marked with yellow stripes and reddish-brown dots. _The Brimstone_ (_Gonopteryx Rhamni_) This, the last member of the present family, is remarkable for the graceful outline of its wings. The costal margins of the fore pair are most beautifully arched, and both pairs are sharply angled on the hind margins. This latter characteristic is quite unique among British butterflies, though we shall presently meet with instances of angular projections on hind wings only. The ground colour of the male (Plate II, fig. 4) is a rich sulphury yellow, with a greenish tinge. That of the female is a very pale greenish yellow. The only conspicuous markings are small saffron spots, one near the centre of each wing. The antennae are red, short, and beautifully curved; but, unlike the two preceding species, the legs are almost white. The eggs of this butterfly are laid in April on the two species of buckthorn (_Rhamnus catharticus_ and _R. Frangula_) by the females that have successfully weathered the winter. They are of a bright yellow colour, and are usually hatched in about a fortnight. The body of the caterpillar is green, and it is thickly covered with little black wart-like projections. A pale stripe also runs along each side. During May and June it may be found on its food plants, and toward the end of the latter month it attaches itself by a silken carpet and belt to the under side of one of the leaves. The chrysalis is of a very peculiar shape, the body being curved, and the wing cases standing out prominently beyond the general surface. Its colour is a bright apple green marked with yellow, and it is so transparent that certain of the structures can be seen through its skin.