These magnificent insects have a singular distribution. The gold-spangled Urania (6 sp.) is characteristic of Tropical America, but a single species of great magnificence occurs in Madagascar. The large but sober-tinted Nyctalemon (6 sp.) is found in the Neotropical, Oriental, and Australian regions.
Family 21.—STYGIIDÆ. (3 Genera, 14 Species.)
These insects are confined to the Palæarctic and Neotropical regions, 2 genera in the former, 1 in the latter.
Family 22.—ÆGERIIDÆ. (24 Genera, 215 Species.)
This family is found in all parts of the world except Australia. Ægeria is most abundant in Europe, but is found also in North and South America.
Family 23.—SPHINGIDÆ. (40 Genera, 345 Species.)
The Sphinx Moths are cosmopolitan. The most important genera are,—Macroglossa (26 sp.), Chærocampa (46 sp.), and Macrosila (21 sp.), all cosmopolitan; Sesia (12 sp.), Europe, Asia, and North America; Deilephila (19 sp.), Palæarctic and Oriental regions, Nearctic region, and Chili; Sphinx (21 sp.), Europe, North and South America; Smerinthus (29 sp.), all regions except Australia. Our Death's Head Moth (Acherontia atropos) ranges to Sierra Leone and the Philippine Islands.
General Remarks on the Distribution of the Diurnal Lepidoptera and Sphingidea.
The Diurnal Lepidoptera or Butterflies, comprehend 431 genera and 7,740 species, arranged in 16 families, according to Mr. Kirby's Catalogue published in 1871. The Sphingidea consist of 135 genera and 1,255 species, arranged in 7 families, according to the British Museum Catalogue dated 1864; and as this includes all Mr. Bates' collections in America and my own in the East, it is probable that no very large additions have since been made.
The distribution of the families and genera of Butterflies corresponds generally with that of Birds—and more especially with that of the Passerine birds—in showing a primary division of the earth into Eastern and Western, rather than into Northern and Southern lands. The Neotropical region is by far the richest and most peculiar. It possesses 15 families of butterflies, whereas the other regions have only from 8, in the Palæarctic, to 12 in the Ethiopian and Oriental regions; and as none of the Old World regions possess any peculiar families, the New World has a very clear superiority. In genera the preponderance is still greater, since the Neotropical region possesses about 200 altogether peculiar to it, out of a total of 431 genera, many of which are cosmopolitan. Comparing, now, the Eastern regions with the Western, we have two peculiar families in the former to 4 in the latter; while the Southern regions (Australian and Neotropical) possess not a single peculiar family in common.