er by the wind, and then deposited eggs which produced
the next year's troop of butterflies; or, lastly, whether an agency was at
work here, of whose nature we are entirely ignorant,--all these are
questions that still remain to be answered. There is, I believe, no
foundation for the opinion sometimes held by entomologists, that this
species prevails at _regular_ periods, such as once in four, or once in
seven years. In fact, for the last two or three years its permanent
residence and appearance among us seems to be established, while, at the
same time, its northward range has been greatly extended, a considerable
number having been taken even _in Scotland_--its existence in that country
having been previously quite unheard of.

The environs of London, especially on the south side, have been abundantly
visited by this charming insect; but its tastes have a decidedly maritime
tendency, and we find it has a marked preference for the _South Coast_;
abounding, again, more especially towards the eastern end. Its favourite
resorts are clover and lucerne fields, though dry flowery meadows, open
downs, and the sides of railway-banks are also the scenes of its lively
flight--for _Edusa_ has indeed a lively flight, and his pursuer has need of
the "seven-league boots," with the hand of {73} Mercury, to insure success
in the fair open race, if that can be called a fair race at all, between a
heavy biped, struggling and perspiring about a slippery hill-side, such as
_Edusa_ loves,--and a winged spirit of air, to whom up-hill and down-hill
seem all one.

In truth, the best way to get _Edusa_ is to watch and mark him down on a
flower, then creep cautiously up till within range, raise the net quietly,
and _strike rapidly downwards_ over the insect, who usually darts _upward_
when struck at; and, in nine cases out of ten, _Edusa_ will be fluttering
under the net. It is not the most heroic style of sport, this, but it fills
the boxes admirably.

The _caterpillar_ is of a deep green colour, having on each side a white
line, marked with yellow and orange. It may be sought for in June and July,
on various plants of the leguminous order, which form its food, such as
None-such Trefoil (_Medicago lupulina_), Lucerne (_M. Sativa_), and Clover.

The _chrysalis_ is in shape between that of the Brimstone, and Cabbage
butterfly, green with a yellow stripe, and rust-coloured dots.

The _butterfly_ seldom is seen on the wing till July, but August