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ARCTIIDAE. Introduction. By Dr. A. Seitz. 
Whereas then on the one hand it appeared advisable to give up many genera based upon a misguiding 
system of neuration, and to unite more than 30 partly rather large Arctiid genera into one and the same 
genus Diacrisia which thus will comprise nearly 200 forms, it was shown on the other hand that in the 
subfamily of Lithosiinae there exist hundreds of forms the neuration of which only applies to one single 
species. In consequence we have an enormous number of monotypic genera, and indeed most genera of 
the Lithosiinae contain only 1—2 rigid, but slightly variable, known forms which, moreover, are so peculiarly 
characteristic that it hardly seems likely that any new species will be discovered which will deprive the genera 
of their mono-or di-typic character. The value of neuration for systematic classification must of necessity be 
but slight in all cases, where it does not represent a phylogenetically constant anatomical document, but 
where its* abnormal differentiation is only brought about by sexual changes in the wings such as the introduction 
of scent-patches, tufts of hair-scales or chitinized plates etc. This is the case with a good many of the 
Lithosiinae, and we must therefore in this group not attribute the same value to the characteristics depending 
on neuration as we justly do wherever we know these to be old-established, constant and but slightly susceptible 
of external influences. 
The foodplants of the Arctianae are so much varied, that we find among them polyphagous species 
which practically refuse no leafy substance. Thus the exceedingly strong mandibles of f. i. Rliyparia purpurea 
render the use of wire-netting instead of gauze for the breeding cages obligatory, while on the other hand 
they enable the caterpillar to eat even the toughest leaves. A. caja may be observed in the open air not 
only to change from one species of plant to the other belonging to the same genus, but to choose also 
representatives of quite different genera, although there may be no lack of the former. Many species change 
even from Mono-to Dicotyletonic plants. Again others like Oeonistis quadra L. the larva of which normally 
lives on lichens, not infrequently have to abandon this food which on account of its increasing numbers 
would be insufficient, and wander along the trunks into the crowns of deciduous or coniferous trees where 
they not rarely do considerable damage. 
Lichens which as a rule are not liked by other caterpillars, are, however, not the only uncommon 
food of the Arctiidae. For many species feed on aquatic plants and must therefore be able to swim, as f. i. 
the American Palustra which live on Potamogeton. Also the larvae of Ecpantheria live in swamps. Many 
Antarctia seem to live on mosses which otherwise are universally refused. True Cannibalism does not seem 
to exist among them in nature, but a lack of water drives them frequently to it. Thus it has often been 
observed in breeding cages which are kept too dry, that the larvae attack freshly made pupae or half pupated larvae. 
On the other hand some species of Arctiidae have decidedly gregarious habits. Thus it is reported 
that Axiopoena maura congregates in great numbers in certain clefts or cavities of rocks. Callimorpha 
quadripunctaria may be often observed swarming in great numbers about Eupatorium, generally crowding 
upon the same blossoms where some of their associates have previously alighted. Also the larvae of Euchelia 
jacohaeae are mostly found in great numbers together on the same bush. The larvae of the Australian Asura 
lydia and Eutane terminalis, which during their feeding period must live apart in order to subsist on the rather widely 
dispersed lichens, assemble under certain rocks in order to pupate, and one may then find whole colonies of 
cocoons closely crowded together. The larvae of Ocnogyna and Utetheisa are often found crowding together 
in great numbers in certain places, and especially of the latter genus the butterflies have been observed 
migrating over the sea in countless numbers. 
In contradistinction to the Palaearctic, mostly gaudily coloured species which for the most part are 
true day-fliers and visit flowers, a good many Indo-Australian Arctiidae only fly in nighttime and never are 
found on flowers. Many species sit in the grass and may be easily frightened, but others are, like our own 
Spilosoma, so lazy that they hardly will open their wings if one throws them into the air. Whereas some 
species are very fond of sipping honey, others, lacking the necessary organs, never take in the form of the 
imago any nourishment. 
Regarding their occurrence we find among the Arctiidae the greatest extremes. In the same way as 
in the Palaearctic Region certain species such as Callimorpha quadripunctaria are found in certain favourable 
localities in astonishing numbers, whereas of others as f. i Hyphoraia festiva hardly one specimen may be 
found in years, thus also we find certain Indo-Australian, especially Antarctic, Arctiidae to be enormously 
scarce, whilst others occur in such astonishing numbers as are probably never observed in other butterflies. 
I saw in India a certain species of Utetheisa whirling about the passing carriage like snow-flakes; at Por.t- 
Adelaide in South Australia I observed whole swarms of Nyctemera arnica; in Bass Street the wind carried 
such masses of this insect from the south coast of Australia upon our ship that the sails were simply covered 
and black with them. In the South of China I brought down hundreds of larvae of Aganais by kicking 
against the trunk of a tree, and the glistening pupae were litterally filling all cracks between the bark and 
cavities in the trees. 
Just as there are some species of Arctiidae which year offer year occur in great numbers and only 
in exceptional cases may be scarce, thus there are others which are never found in any number, and again 
others having a periodical appearance which show only rarely a great increase in numbers. The greatest 
regularity seem to have the Lythosiinae , of which I only know Atolmis ( Gnophria) rubricollis and Oeonistis 
