AEGERIIDAE. General Topics. By Dr. A. Seitz 
775 
23. Family: Aegeriidae. 
There are certainly more than a thousand species forming this family the prior name of which, “Sesiidae ”, 
was changed into Aegeriidae owing to the restitution of the generic name “ Sesia ” for a Sphingid genus. Quite 
a number of species will yet be discovered or published in a short time. The distribution of the genera and species 
has been dealt with in Vol. XIV, p. 516; according to these statements almost as many forms have been described 
from the Indo-Australian fauna as from the palaearctic and Ethiopian regions; the reason why not cpiite so 
many names have been granted to the African Aegeriidae as to the palaearctic forms, is not that this fauna 
can boast of a greater abundance of forms, but that the more numerous and exhaustive authors of the palaearctic 
regions were more lavish with denominations. 
Regarding the age and origin of the Aegeriidae, the experts’ opinions differ very much (cf. Vol. XIV, 
p. 514) by reason of certain peculiarities found united in the Aegeriidae, while they rather exclude one another 
in other families. The members of the Aegeriid family are highly specialized by a most unequalled mimicry, 
while quite a number of characteristics prove them to be closely affined with the most primitive Heterocera 
known. We can therefore only suppose that a single branch of the very old tribe of most primordial lepidoptera 
has pursued a very modern course of development and has partly taken quite new routes, so as to be able to 
exist in spite of being exposed to all kinds of dangers. The great consistency of all the Aegeriidae hitherto 
known also argues distinctly in favour of this supposition, since all of them — with but very few exceptions -— 
are structured, coloured and organised according to the same principles. The Indo-Australian representatives 
of the family show the very same habits as those from other faunae: nearly all of them copy the much dreaded 
Aculeatae, the imitation being often carried through with a most astounding cunningness, and not only con¬ 
cerning somatic but also physiological and bionomic details. 
We might therefore greatly wonder at Ebich Haase, in his “Researches on Mimicry”, passing over 
the Aegeriidae with but few references, although he acknowledges the advanced degree of their adaptation 
to the Aculeatae, instead of treating them quite specially and in detail. But Haase advances in his treatise 
as the preliminary condition for proved “mimicry” the assumption that not the family character itself of mimetic 
species discloses this exterior of Aculeatae as an essential feature, which must then not be regarded as a garb 
forced upon the species by the imitation. Thus Haase considers it an impossibility to regard the exterior of 
the Aegeriidae as “boi’rowed”, however wasp-like it may look; it is then no more a product of mimicry, but the 
family-garb appertaining to the whole group altogether. But in fact the imitation effected by the Aegeriidae 
is by no means schematic, but it is expressed in most varied ways and refers to all kinds of organs. The hyaline 
wings might be regarded as a family character which is very rarely denied; but the very common Indo-Australian 
genus Melittia does not only adapt itself to the bee’s shape by its hyaline wings, but it also copies the coating 
of the bee’s legs, which are sometimes even covered with yellow-pointed hair, these tiny points of the hair repre¬ 
senting the pollen of certain blossoms, that usually sticks to the copied bee’s legs. The transformation of the 
antennae neither takes place according to the same principles in all the Aegeriidae. Moreover, the strangulation of 
the centre of the body, the so-called “wasp-waist”, is achieved in different ways. It may sometimes be actually 
produced by a real attenuation of the abdomen, while in other cases white or yellow scales are laid over the 
sides of the base of the abdomen, whereby this part is covered and only a narrow black middle stripe is left, 
so that the wasp-waist is — so to speak — “painted” on the surface of the dorsum. Another fact to be mentioned 
is that there are also some Aegeriidae copying other animals which do by no means belong to the Aculeatae. 
