Publ. 1. XI. 1926. 
General Topics. By Dr. A. Seitz. 
LYMANTRIIDAE. By Dr. M. Hering. 
129 
of the world. The most conspicuous African species is presumably the 3 of the large black and white Abynoiha 
preussi the life-history of which, however, is entirely unknown to me. The genus Numenes, which in India assumes 
an Arctiid-like colouring, occurs also in the Ethiopian region though with a protective colouring. Besides whitish 
hyaline or pale yellow wings, the apical portions of which are bordered with blackish, some species exhibit 
a very conspicuous lustrous white or dark yolk-coloured exterior, so that the Porthesia, Artaxa and others 
may be seen from afar sitting on the trunk. These are above all those species the thorax or hind-margin of 
which exhibits the above-mentioned conspicuous hairing, and wherever this is not the case, in fact the existency 
of the species is so much menaced that make mimicry necessary. Thus nearly all the Lymantria- species of 
the monacha group in Eastern Asia are adapted to the bark of fir-trees to such a degree that the insect is well 
protected and difficult to discover, whereas the European Ocneria monacha with its glaring white exterior 
traversed by black dents is to be seen from a great distance. This behaviour of monacha changes, as it were, 
before our own eyes, since the grey forms that were but very little known a hundred years ago, already predo¬ 
minate to-day in many districts, particularly in those years, when the imago does not occur in great numbers *). 
Although nothing is known of a perfect seasonal dimorphism in the Lymantriidae, yet the enormous 
change of their occurrence proves their being very dependent on the weather. A great many species are of 
annual occurrence and that not only in districts, where this change might be due to special measures of cultivation. 
Like all the old families of insects, the Lymantriidae are also of a great fertility, so that, if all the other conditions 
are favourable, they generally propagate rapidly in enormous masses. At such occasions they may also be 
migratory, though only in very few species of them, since the 9? of most of the Lymantriidae are lazy and 
unwieldy, if not unable to fly at all. 
The larvae are generally very polyphagous, and particularly remarkable by some species being able 
to feed from either leaves or conifers according to the circumstances. In other, likewise phylogenetically old 
families we find a similar behaviour, as for instance in those feeding on lichens ( Oeonistis quadra) which, in 
case of their rapid propagation or if the lichens sometimes fail to appear, may also feed on leaves or on conifers. 
In the mostly very plain colouring of most of the Lymantriidae , that recurs in nearly all the lepidopteral 
families, we frequently meet with resemblances both with members of the same family and with Geometridae 
or species of other lepidopteral groups, and they do not exhibit any striking characters that might be regarded 
as mimicry, which as in all the other phylogenetically old families seems also here to be entirely absent. 
A very strange peculiarity of some Lymantriidae, the purpose of which is quite incomprehensible to 
me, is exhibited by the centre of the thorax, which is otherwise densely covered with woolly hair, presenting an 
entirely hairless place, thus a so-called baldness, as it is often caused in other Heterocera- by their being damaged 
in flying about and by frequent collisions. As we can never ascertain in the captured insect, whether this bald 
metanotum, where the bare chitine is to be seen, is genuine or acquired, I had also always considered this to 
be due to injuries. Only when I noticed an entire homogeneousness of these bald places in a great number 
of evidently freshly crept out Epicoma, I made experiments with breeds **) which proved the imagines of 
this genus being yielded from the pupae with a bare metanot um. Nothing is known to me of a similar behaviour 
in the African species; but as this can only be ascertained in the live and quite fresh insect before its first 
flight, it may also occur in the Ethiopian region, without having been noticed, as was the case in the Austra¬ 
lian region. 
Lyman tri i dae. 
In the African region this family seems to have attained the highest degree of development . More than 
800 species are enumerated in the following pages, and probably there will be many new species added on 
the country being methodically explored. The forms vary exceedingly not only in the colours but also in the 
structure. Species with absent or stunted vein 5 of the hindwing are suggestive of Noctuids, whereas in other 
genera vein 5 is so far removed in front, that they resemble thereby the Notodontidae from which they are 
separable by the Noctuid-like tympanal organ. From the Pterothysanidae they are distinguished only by the 
presence of a frenulum, and certain genera exhibit, without counting this characteristic, such a great conformity 
that the Pterothysanidae may be partly denoted as Lymantriidae that have secondarily lost the hooking bristle. 
The number of veins in the forewing is variable; in general there are 12 veins present, the radial branches 
being partly forked. In many genera there is an accessory cell, though this mark is by no means constant; 
in certain genera there are species in which the single individuals may be with an accessory cell or without it. 
Sometimes single radial branches anastomose, particularly the veins 8 and 9 in the forewing. The anal vein (1 c) 
*) It is a remarkable fact that this melanism has nothing to do with the so-called industrial melanism; on the 
contrary, the grey exterior of the Ocneria monacha is met with in the direction from east to west. (Seitz.) 
**) In New South Wales I bred Epicoma tristis and melanospila. 
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