ecies and individuals, and
consists of fine broad-winged butterflies of a glossy or metallic
blue-black colour, adorned with pure white, or rich blue, or dusky
markings situated round the margins of the wings. Danais has generally
more lengthened wings, of a semitransparent greenish or a rich brown
colour, with radial or marginal pale spots; while the fine Hestias are
of enormous size, of a papery or semitransparent white colour, with
dusky or black spots and markings. Each of these groups is mimicked by
various species of the genus Papilio, usually with such accuracy that it
is impossible to distinguish them on the wing.[101] Several species of
Diadema, a genus of butterflies allied to our Vanessas, also mimic
species of Danais, but in this case the females only are affected, a
subject which will be discussed in another chapter.

Another protected group in the Eastern tropics is that of the beautiful
day-flying moths forming the family Agaristidae. These are usually
adorned with the most brilliant colours or conspicuous markings, they
fly slowly in forests among the butterflies and other diurnal insects,
and their great abundance sufficiently indicates their possession of
some distastefulness which saves them from attack. Under these
conditions we may expect to find other moths which are not so protected
imitating them, and this is the case. One of the common and wide-ranging
species (Opthalmis lincea), found in the islands from Amboyna to New
Ireland, is mimicked in a wonderful manner by one of the Liparidae (the
family to which our common "tussock" and "vapourer" moths belong). This
is a new species collected at Amboyna during the voyage of the
_Challenger_, and has been named Artaxa simulans. Both insects are
black, with the apex of the fore wings ochre coloured, and the outer
half of the hind wings bright orange. The accompanying woodcuts (for the
use of which I am indebted to Mr. John Murray of the _Challenger_
Office) well exhibit their striking resemblance to each other.

[Illustration: FIG. 24.--Opthalmis lincea (Agaristidae). Artaxa simulans
(Liparidae).]

In Africa exactly similar phenomena recur, species of Papilio and of
Diadema mimicking Danaidae or Acraeidae with the most curious accuracy.
Mr. Trimen, who studied this subject in South Africa, has recorded eight
species or varieties of Diadema, and eight of Papilio, which each mimic
some species of Danais; while eight species or varieties of Panopaea
(a