Before entering into details, it will be as well to sketch some of the broad features of butterfly decoration. In the first place they are all day-fliers, and light having so strong an influence upon colour, there is a marked difference in beauty between them and the night-flying moths. A collection of butterflies viewed side by side with a collection of moths brings out this fact more strongly than words can describe, especially when the apparent exceptions are considered; for many moths are as brightly coloured as butterflies. These will be found to belong either to day-flying species, like the various Burnets (_Zygæna_), Tiger Moths (_Arctia_), or evening flyers like the Hawk Moths (_Sphyngidæ_.) The true night-flying, darkness-loving moths cannot in any way compare with the insects that delight in sunshine. We see the same thing in birds, for very few nocturnal species, so far as we are aware, are brilliantly decorated. Another salient feature is the difference that generally exists between the upper and lower surfaces of the wings. As a rule, the upper surface is the seat of the brightest colour. Most butterflies, perhaps all, close their wings when at rest, and the upper wing is generally dropped behind the under wing, so that only the tip is visible. The under surface is very frequently so mottled and coloured as to resemble the insect's natural surroundings, and so afford protection. It does not follow that this protective colouring need be dull, and only when we know the habit of the insect can we pronounce upon the value of such colouring. The pretty Orange-tip has its under wings veined with green, and is most conspicuous in a cabinet, but when at rest upon some umbelliferous plant, with its orange tip hidden, these markings so resemble the environment as to render the insect very inconspicuous. The brilliant _Argynnis Lathonia_, with its underside adorned with plates of metallic silver, is in the cabinet a most vivid and strongly-marked species; but we have watched this insect alight among brown leaves, or on brown stones, outside Florence, where it is very common, and find that these very marks are a sure protection, for the insect at rest is most difficult to see, even when it is marked down to its resting-place.