This magnificent butterfly is so exceedingly rare that M. Boisduval, whose knowledge of the European Collections is very extensive, questions whether there exists any other specimen than that originally figured by Drury. Mr. Jones also, whose splendid Collection of Drawings are so frequently quoted by Fabricius, copied this insect, figuring both the upper and under sides, which figures have been lately published by Mr. Donovan in his Naturalist's Repository. Mr. Donovan also adds, that from the manuscripts of Mr. Drury, "we find that he received this insect in 1775, from Mr. Smeathman, an assiduous and very intelligent naturalist stationed at Sierra Leone."
"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.
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.)