INDARBELIDAE. General Topics. By Dr. A. Seitz. 
803 
24. Family: Indarbelidae. 
This family comprises only about 20 Indian Heterocera forms the grouping of which has been frequently 
changed, as we stated already in Vol. XIV (p. 501). It is undoubtedly a very old group exhibiting 
entirely the character of the so-called “ Microlepidoptera” . Like most of the Archaic genera, they are absolutely 
nocturnal, and as we mentioned in Vol. XIV, they can only be captured on the light. In Africa from where 
we had enumerated more than 100 species (Vol. XIV, p. 502—512, pi. 78) the family plays a much more im¬ 
portant part than in the Indian fauna where its range is confined to the tropical districts between India, the 
Philippines and Formosa. Considering the old age of this lepidopteral group it is a remarkable fact that no 
representatives of it have yet been found in Australia and New Zeeland. 
The Indian genera differ from those occurring in Africa to such an extent that the Africans have been 
separated as a special family as which they were also treated in the African Part of this work. The Mada- 
gassic Metarbelid species Saahnulleria stumpffi figured there from the type is the most imposing palaearctic 
species exhibiting a very characteristic African peculiarity: the two-pointed anal tuft corresponding to the 
monstrous hair-tuft in the Indian region, as we notice in the figure of Indarbela campbelli (93 g). 
In opposition to the African Arbeliclae which were given the family name of Metarbelidae, the Indian 
species were separated as Indarbelidae with the character of a special family. This is justified to a certain 
degree, for very ancient lepidopteral groups have distinctly developed some structural peculiarities, whereas 
recent forms mostly exhibit more superficial differences. Nevertheless it will for the sake of synopsis — 
not be advisable to increase the number of families unnecessarily. The relations between the Indian and the 
Ethiopian Arbelidae are so very obvious that they may be easily comprised. Some Arbelidae seem to be 
merely the tropical representatives of palaearctic members of the genera Holcocerus or Dyspessa, and their 
habitus and behaviour in their patria is often exactly like that ascertained in palaearctic Cossidae from the 
said genera. The live and dead specimens of Indarbela quadrinotata tetraonis are the very images of an in¬ 
tensely marked Holcocerus nobilis, so that the resting lepidopteron can hardly be distinguished, and there 
are doubles to be found for nearly all the Indarbelidae : sometimes in the palaearctic region among the Cossidae, 
sometimes in Africa among the Metarbelidae. The habitus of Ind. magma and minima is decidedly more 
like that of the African Metarbelid Salagena transversa (Vol. XIV, pi. 78 d) or of Aethiopina argentijera (ibid. 78 e) 
than like that of the members of their own genus. The antennae, as we stated already in Vol. II, p. 421, 
have sometimes been regarded as decisive for the system in cases when they are inappropriate for it. We 
had also mentioned there that they even sometimes vary individually and may even differ considerably from 
each other topographically, as in Cossus CS °f the same species originating from different habitats or dis¬ 
tricts. On the other hand, certain Indarbelid species sometimes exhibit such great resemblances to each 
other that it is difficult to distinguish them, and some of them might be regarded merely as the representa¬ 
tives of other species in other countries. 
Little is known of the early stages. One larva has been described by R. Mell, that of Indarbela 
obliquifascia. Its exterior and habits are entirely Cossid-like. In the fork of a branch it eats a hole large 
enough to hide itself therein. From this place it browses the bark at night and, by means of dirt-lumps 
spun over with tiny chips of bark, it provides a cover below which a tunnel runs along, very similar to the 
one constructed by termites. The pupation takes place in the wood and, as in the Cossidae and Aegeriidae, 
the pupa shoves itself far forward before the imago emerges. Similar habits are reported by J. de Joaunis 
of the larvae of Ind. dea (93 h), which were found in Tonkin on the trees of Erythroxylum coca having been 
imported from South America. 
