Publ. 23. III. 1926. 
9 
Preface. 
In Vol. XIII (p. 1 to 7) we have attempted a very short sketch on the African lepidopteral fauna in 
particular consideration of the Rhopalocera, in which the Heterocera were but briefly touched. The abundance 
of the two groups in Africa is far inferior to that in the Indian and South American tropical regions, though 
the single parts of this gigantic continent are in this respect by no means uniform. 
In the Rhopalocera, of which about 1200 species are described, the proportion of the African Fauna 
to the other districts was such that of the Ethiopian region about twice as many species are known as of the 
whole palearctic region; whereas the Indo-Australian Fauna contains half the number of species more and 
the American Fauna being particularly rich in insects almost three times as many species. As to the Heterocera, 
such a summary estimate is impossible, particularly since the African Microlepidoptera are still very incompletely 
known and in some districts of that continent have even not yet been collected at all. 
The greatest abundance in lepidoptera generally occur -— as also in other parts of the world — in 
those districts of Africa where very high temperatures are combined with rather copious rainfalls distributed 
among a great many months. These rainfalls depend again on the currents of air exhibiting a system 
frecprently changed and disturbed by local causes, but still being rather constant, and based upon the following 
processes. The immense surface of the interior regions of Africa is heated by the sun to a very high degree, 
since the whole Ethiopian region, beginning to the south of the Sahara, is situate in the tropical zone, with 
the sole exception of Cape Colony, which fact is not repeated in any other fauna of the world. The air, being 
thus heated, naturally ascends drawing after it the cooler air lying over the oceans into the vacuum generated 
by its escape. Being nowhere obstructed by lofty mountains, as for instance the American Cordilleras, the 
Alps, the Himalaya, or the Japanese Mountains, the humid winds in West Africa are able to penetrate far 
into the interior of the continent, and the copious rainfalls produced thereby drench a vast part of the country, 
extending from Senegambia with but very few interruptions to the south of the Congo District. A densely 
felted vegetation covers the Hylaea or the district of the tropical rain-forest, an immense surface of West Africa. 
Only to the south of Angola, where the nights produce a great cooling down particularly in the Ovanrpo and 
Herero Districts, this continuous inflow of humid sea-air stops and the precipitations become rare and scanty; 
instead of the exuberant wooded country there are extensive grassy steppes, being in the northern parts inter¬ 
mixed with shrubbery, whilst in the southern parts there are sandy plains always growing waster and being 
in some parts entirely desolate. 
The abundance in lepidoptera accommodates itself to these conditions. From the African Hylaea we 
have become acquainted with quite a number of forms among the Rhopalocera of the 13th volume, some of 
which were gigantic insects, such as Pap. antimachus with an expanse of nearly % m. The Nymphalidae had 
also attained an imposing size in the genera Charaxes, Euphaedra, Salamis, and Hypolimnas. But nevertheless 
there were by far fewer gigantic forms in Africa than in the tropics of Asia and America; the Hestia and 
Zeuxidia of India, the Morplno and Caligo of South America are unparellelled in Africa. The same is the case 
with the Heterocera. Only in the Saturniidae Africa is superior to certain other tropical districts; of Sphingidae 
there occur but few gigantic forms (LopJwstethus demolini), and the Ethiopian forms of the other Phalaenic 
family are rarely more than medium-sized. 
Those not being acquainted with the nature of the country will be impressed by many districts of the 
Ethiopian region as being very poor in lepidoptera. Other orders of insects, such as the Orthoplera, e. g. 
grasshoppers, Mantids, Termites, in many places also Hymenoptera, seem evidently to predominate. The 
reason of it is that most of the districts visited at first by the new-comer, owing to their being more easily 
XIV 
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