"From the observations of Mr. Smeathman it may be imagined that this insect is not unfrequent in that particular part of Africa, but that its capture is attended with considerable difficulty, as well from the manner of its flight, as the time when it appears on the wing; it is seen only in mid-day, when every exertion under the direct influence of a vertical sun must be painful to an European. Its flight is also remarkable for its velocity, and to increase the difficulty of taking it, the insect frequents only the upper branches of the trees, from whence it darts and glances from one branch to another, and never descends nearer to the ground than the height of eight feet. Mr. Smeathman observes also, that it turns its head about instantly to the glade or path, and will not suffer any person to approach within 'striking distance' of it, but will dart away on the least motion of the body; if the naturalist however exerts his patience, it will at last become more familiar and careless, and is then to be caught upon some particular branch, to which it will appear more attached than to another." Mr. Donovan however suggests, that the insect must be not only exceedingly local, but also of great rarity. PLATE II. [Illustration] HEPIALUS CRASSUS. Plate II. fig. 1. ORDER: Lepidoptera. SECTION: Nocturna. FAMILY: Hepialidæ, _Steph._ GENUS. HEPIALUS, _Fabr._ Hepiolus, _Illiger_. Phalæna (Noctua), _Drury_. HEPIALUS CRASSUS. Alis anticis albis, fusco, cinereo, badioque variis, apice irregulariter albo, lunulâ magnâ fuscâ; posticis griseo-fuscantibus. (Expans. Alar. 7 unc.) SYN. Phalæna (Noctua) crassa, _Drury_, _App. vol._ 3. HABITAT: Sierra Leone. _Upper Side._ Antennæ filiform, whiteish at the base, black at the tips. Head whiteish, small. Thorax whiteish, having two black tufts of hair on the shoulders, and two next the abdomen; upper part yellowish brown. Abdomen dark brown, almost black, being ringed and edged with dark grey. Anterior wings whiteish, intermixed with many patches and irregular spots of grey and dark brown. Posterior wings darkish grey brown, but lighter along the posterior edges. _Under Side._ All the parts on this side are of a dark yellow brown, of the same colour with the upper side of the inferior wings. Abdomen rather lighter, with a dark brown line running along its middle from the thorax to the anus. {3}SPHINX IDRIEUS. Plate II. fig. 2. ORDER: Lepidoptera. SECTION: Crepuscularia. FAMILY: Sphingidæ, _Leach_. GENUS. SPHINX, _Linn._ SPHINX IDRIEUS. Corpore alisque anticis viridibus, posticis fulvis margine nigro. (Expans. Alar. 2 unc.) SYN. Sphinx Idrieus, _Drury_, _App. vol._ 3. (1783.) Sphinx Medea, _Fabr. Ent. Syst._ III. 1. _p._ 363. _No._ 23. (1793.) HABITAT: Africa (_Drury_). "Africa æquinoctiali" (_Fabr._).