URANIIDAE. General Topics. By Dr. A. Seitz. 
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13. Family: Uraniidae. 
Regarding this chapter we refer the readers to what has been said about the Uraniidae in Vol. II, 
p. 275; Vol. X, p. 93, and Vol. XIV, p. 387. Of the different American groups which contrast strictly with each 
other the Uraniidae are represented by the typical genus Urania which almost exactly corresponds to the 
African Chrysiridia and — though only in the stouter structure — to the Indo-Australian Alcidis. The nocturnal 
Sematura are distinctly separated from the diurnal Urania ; and even to the extent that they have recently 
been taken out of the family of Uraniidae. There is no parallel case of these Sematura in Africa, whereas they 
are almost exactly represented by the Nyctalemon in the Indo-Australian region, so that Walker was even 
induced to describe them as Sematura. In America another group is united with the latter, i. e. the Coronidia- 
group containing almost 30 known forms and probably several unknown forms, so that it represents the largest 
group of the whole family, if the more remote Epiplernidae are separated from it, as we have tried to do in Vol. X. 
On several occasions we have treated upon the most peculiar geographical distribution of the family. 
The unmistakable affinity between the South-East African Chrysiridia and the purely American Urania is too 
distinctly evinced by their exterior, habits and — as we know now — by their early stages to admit the 
explanation of their resemblance by the congruence of their conditions of life. Owing to their long-lasting 
persevering flights and the roving spirit of many Urania it is rendered very difficult to understand the oico- 
logical conditions of the group. It is particularly the statements about the range of the American genus Urania 
which are so contradictory that we can only come to the conclusion that some species immigrate temporarily 
and then disappear again. Vast tracts of the South-American continent are positively professed to lack the 
genus Urania, whereas such great numbers of them are reported from small islands situated near the coast 
that one cannot conceive why this excellent flier has not mastered this small stretch of water. A parallel case 
is met with in the closely allied lepidopteral genus Chrysiridia in Africa, since two distinctly separated species 
of the genus live on the opposite coasts of South-East Africa and Madagascar, both species being apparently ab¬ 
sent in the Europa-Island as well as the Comoro-Islands situated almost exactly midway between them. Whilst 
the Brazilian Urania brasiliensis is reported to be common in some islands, but not to reach the opposite 
continent, Guppy states that the northern Urania leilus continually wanders from the Venezuelan continent 
to the I. of Trinidad situated quite near to it and that, whilst only single females deposit their eggs there, the 
main swarms leave the island again and return to the continent. 
A very similar roving spirit is also shown by the other species of Urania , and this peculiarity is also 
often mentioned in literature regarding U. julgens and the West-Indian U. sloanus. Members of the family are 
even reported to swarm together before their departure as swallows or other birds of passage are in the habit 
of doing. They gather together within few days and, in flying off, they sometimes form real swarms. But this 
is by no means the case every year; on the contrary, only single specimens are often met with during a whole 
decade — the same is reported by Dr. Reuss of the African Chrysiridia —, or the species seems to be entirely 
missing, until all of a sudden their number increases from one hour to the other and the lepidoptera dash about 
in crowds, sometimes even flying from the coast out to sea. 
The places where the swarms gather are generally strictly localized areas to which the lepidoptera 
crowd together from all the surrounding districts. They frequently rest on the leaves of hanging wigs, keeping 
their wings flatly spread out, the forewings somewhat lowered, so that they partly cover the hindwings. The 
insects settle upright, but then quickly turn round until they sit with their heads down; the same behaviour 
is also stated by R. Mell of the Indian Nyctalemon. The imagines are often seen playing together, forming- 
bands of 6 and more specimens, but apparently they do not fight with each other, as the butterflies frequently 
