Some species are most remarkable for their excessive _localness_ (as it is called), or, limiting their range to an exceedingly small circumscribed space; so much so, that some rare species have been known to haunt just one corner of one particular field, year after year, while not a single specimen could be found in all the neighbouring fields, though precisely similar, to all appearance. This phenomenon is quite inexplicable with regard to insects endowed so pre-eminently with locomotive powers as butterflies are. The local nature of his game should, however, induce the collector to leave no nook or corner unexplored when he is "working" a district; as the passing over (or rather, neglecting to _pass over_) a single field may lose him the very species it would joy him most to find. [Illustration: VII.] {45} I would also advise the beginner--and, indeed, all but the very experienced hands--to catch, not necessarily for slaughter, but for inspection, every attainable individual whose species he cannot positively declare to when on the wing, lest he pass by some rarities unawares. Thus the valued Queen of Spain, and the much-disputed _Dia_ Fritillaries, the _Melitæas_, the Brown Hair-streak, and (on the mountains) the rare _Erebias_, perhaps some new to this country,--any of these might be mistaken by a novice for some of the commoner brown species. Among the "Whites," too, the Black-veined White, that great prize, the Bath White, and the white varieties of the Clouded Yellow and Clouded Sulphur, might share the same fate, or fortune rather, of being reckoned as "Cabbage Whites." Then, with the "Blues." Who is there that could at once distinguish with certainty the very rare Mazarine Blue (_P. Acis_) from the common Blues when on the wing? Perhaps it would turn out to be less rare than supposed, if all the Blues in a fresh locality were netted as they came near, and set at liberty after passing muster. Why, only last season a very curious Blue,[7] never before observed in this country, was captured near {46} Brighton by a collector, who, at the moment, thought it was only a Common Blue, so precisely similar did it look when flying.