ARCTIIDAE. Introduction. By Dr. A. Seitz. 
231 
4. Family: Arctiidae, Tiger Moths. 
The number of American Arctiidae is very considerable, if one includes the groups having been branched 
off by others as Hypsidae etc. This has been done here, referring to the fact that the venation of the Arctiids 
has not been awarded the leading part which is indisputably the case in other groups. I have already hinted 
at this in Vol. II, p. 43, and in Vol. 10, p. 105. An application upon the American fauna would mean a system 
based upon exclusive relations in the veins, as for instance the elimination of the Pericopini, as it effected in 
the palearctic regions the elimination of the Callimorpha, in the Indian region that of the Aganais from the 
family of the Arctiids; in spite of Hampson’s precedence, we cannot make up our mind to such a bold proceding. 
We must, however, point out that neither the variegated colouring nor the hairy dress of the larva 
have been the reason why we inserted the Callimorphini, Pericopini, Hypsini, Phaegopterini etc. among the 
Arctiidae. We find an Arctiid-like monitory exterior also in the $$ of the Lymantriids ( Numenes separata 
Vol. II, t. 22 f), in Agaristids and many Geometrids. But a close alliance seems to us to be exhibited by the 
conformities of details that are difficult to consider as the symptom of convergency. The very uniform smell 
of oil noticeable in the genuine Arctiini as well as in the Callimorpha, the Aganais and Pericopis, is produced 
by the development of a sharp, protective, yellow secretion emanating in thick drops from two apertures in 
the neck of the insect, a symptom which seems to be of quite a similar nature and of exactly the same effect 
in the Callimorpha, the Arctia, Spilosoma etc. In the Apantesis, Arctia etc. a large, yellow drop flows from the 
sides of the neck, on being disquieted, in certain Pericopini, the secretion profusely intermixed with air is 
discharged by jerks as a yellow foam, whilst the insect is groaning and moaning. It lias an acid, somewhat caustic 
taste and protects these insects against their enemies to such an extent that they do not hide, but show them¬ 
selves in a most conspicuous way by glaring colours, and often play in broad daylight, evidently shunned. 
Another conformity of the Callimorphini, Hypsini, Pericopini etc. with the Arctiini consists in a pecu¬ 
liar, cracking noise produced by the insects in flying. It is not equably audible to the human ear in all the 
species, but in many Arctia, in Nyctemera and Aganais it is distinct, and in Parasemia plantaginis, Callimorpha 
dominula, Spilosoma (Dionychopus) niveum even loud. 
The larvae are all well haired, though not all are shaggy or furry. The hairs are mechanically undoubtedly 
quite a good protection, chemically, however, of very little effect. They also seem generally to have the purpose 
of a mechanical effect, for they are often very strong; Arctia has fleece-like compact hair which in Ecpantlieria 
already grow so hard that they have the effect of spikes, while in the Pericopini they are still more specialized. 
The latter insects are covered with them in the shape of almost steel-hard, brittle, pointed thorns, which are 
not ramulous like those of the day-butterflies of or the Dirphia and Automeris, but not less pointed than those, 
and by which one is easily stung on touching the insect carelessly. Safeguarded by this protection, the larvae 
of the Arctiidae mostly live quite freely, feed in the sunshine, sit freely on the earth or on their food-plants in 
day-time, and but few, such as some Ocnogyna, Cletis, Callimorpha etc. hide superficially during the day. 
Common to nearly all the Arctiidae is the behaviour and exterior of the pupa. It is mostly as smooth 
and bright as a mirror, as if it were polished, but by no means so thick-shelled as we find it in most of the other 
pupae of a porcelain lustre, the Bunaea, Gynanisa, Agarista etc. The web is very scanty, sometimes it does 
not even deserve this name and is then confined upon some criss-cross threads in which the pupa is hung up 
almost without any protection. In some species, such as Arctia hebe, Rhyparia purpurata, Hyphoraia aulica etc. 
it is to be wondered at how the little protected and rather delicate pupa is exposed to the roughness of 
the weather often increased by a severe winter. The pupae of the Lithosiini are shut off in a wide slit of the 
bark only by some cross threads, and consequently approachable to all their enemies.. In a similar way, the pupae 
of Aganais being gregariously established in the slits of the bark are almost unprotected. The pupae of some 
Pericopini, however, are the most conspicuously and the most freely suspended in a few threads fixed 
between the tips of the twigs of isolated bushes, so that I occasionally thought to see a cobweb from the distance 
in the centre of which the pupa, as smooth as porcelain, was suspended like a spider. 
Beside these peculiarities of peculiar conformity being found in by far the greatest part of the Arctiidae 
according to our conception there is also a far extending likeness noticeable in the contours of the wings, in 
the structure of the body, to a certain degree also in the colouring. We do not see anywhere mimicry, 
nor is there hardly ever any adaptation noticeable. The Apantesis shine brightly by their variegated colours, 
the Lithosiini by their yellow, the Spilosoma and Haploa by the snowy white, the Belemnia by their mag- 
