# Zoological Illustrations/VolI-Pl11

DRUSILLA Horsfieldii.
Generic Character.
    Antennæ mediocres, clavâ productâ, gracili, cylindraceâ. Palpi breves, compressissimi, obtusi, remoti, linguam non attingentes; lateribus utrisque hirsutissimis, articulos obtegentibus. Abdomen (in maribus) 7-articulatum: 1mo longissimo, ultimo simplici, truncato, suprà integro, subtus unco incurvato, valvis nullis. Alæ anticæ (in maribus) basi posticâ dilatatæ, fasciculum in alas posticas obtegentes.
    (Obs. Alæ integerrimæ, subdiaphanæ, posticæ magnæ, orbiculares. Pedes antici spurii; antennarum articuli basales ad apicem incrassati.)
Typus Genericus Papilio Jairus. Fabr.
    Antennæ moderate, the club lengthened, slender, cylindric. Palpi short, much compressed, obtuse, remote, not touching the tongue, covered equally on both sides with thickset hairs concealing the joints. Abdomen (in the male) 7-jointed, the first very long, the last simple, truncate, and entire above, without valves, and with an incurved hook beneath. Anterior wings (in the male) dilated at the posterior base, concealing a tuft of hair on the inferior wings.
Generic Type Papilio Jairus. Fabr.
    (Obs. Wings very entire, sub-diaphanous. Hinder wings large, orbicular. Fore-legs spurious. Basal articulations of the antennæ thickened at the end.)
Specific Character.
    D. alis anticis angustatis, fuscis, concoloribus; margine posteriore et exteriore æqualibus: posticis albidis; margine exteriore fusco, suprà uni-ocellato, subtus bi-ocellato.
    Wings, anterior, narrowed, the posterior and exterior margins equal, uniform brown; posterior cream-coloured, with a brown margin, one ocellate spot above, and two beneath.
This new and elegant insect was discovered by my worthy friend Dr. Horsfield (after whom I have named it) in the interior of Java: it forms a part of the extensive collections made there by this zealous naturalist for the East India Company, and which will make a most important addition to our present confined knowledge of the productions of that interesting island: indeed these collections exceed in extent, preservation, and value, any which have been brought to this country.
The general resemblance of this species with Papilio Jairus of Fabricius is so great, that it might pass on a cursory view as a mere variety, did not the form of the anterior wings at once point out the difference. In the present insect the posterior and exterior margins are of equal length, giving a narrow appearance to the wings, much resembling some of the true Papilionidæ; but in P. Jairus, these wings are much broader, more obtuse, and the length of the posterior margin much greater; other minor differences exist in the colouring and markings. My valued friend A. H. Haworth, Esq., F.L.S., &c. possesses a fine pair of the true P. Jairus in his rich and extensive collection; and the liberality with which it is constantly and freely opened to me, deserves my warmest thanks.
From these two species I have formed the present genus, the characters of which will distinguish it from that of Hætera (Fabr.), a scanty genus confined to South America; and this seems to occupy its place in India: both will come in the natural family of Hipparchidæ. Only one specimen (a male) exists in Dr. Horsfield's collections; I could not therefore dissect the mouth, &c. On the inner borders of the inferior wings is a lengthened tuft of fine hairs: the anus beneath has on each side an obtuse lengthened process, partially attached, and which appears to supply the place of the lateral valves. It is represented on a sprig of
Gærtnera racemosa,
which, although differing slightly from the figure of Dr. Roxburgh's Coromandel Plants, p. 19. t. 18, Dr. Horsfield considers as the same plant. The Javanese name is Kakas.