516 
AEGERIIDAE. Introduction by Dr. A. Seitz. 
These fictitious trousers of the Melittia are not only of about the same shape as those of bees, but also 
their colouring is unmistakably copied; in quite a number of cases we even find the collected pollen imitated 
by a fictitious golden yellow layer on the outside of the brush of the hind tibiae (Mel. auriplumia, 77 f, and 
victrix, 77 g). In order to complete the masking they also exhibit a stout body, a bee-like thickened abdomen, 
contrary to the Aegeriidae copying the Ichneumonidae or Sphegidae (e. g. the Synanthedon). 
The chief thing of this protective mimicry being only the outward appearance and not the strict 
accuracy of the copy, the most conspicuous formations of the models have mainly been copied. Whilst the 
bees exhibit the collective trousers being packed with pollen, the Sphegidae most remarkably show prolonged 
hind tibiae and femora signifying organs for carrying captured animals. Thus we see the hindlegs of the blue 
copyists of Sphegidae or Pompilidae monstrously prolonged ( Megalos , gigantipes, 77 e) though not brush-like 
expanded, but by the appressed dense fur and thickened calibre they copy the strong musculous prehensile 
organs of their models. The Aegeriidae of the Ethiopian region behave exactly like the neotropical Syntomidae 
of the genus Macrocneme which likewise copy the wasps of the genus Pepsis not only in shape and colouring 
of the wings, but which also most strikingly let their prolonged and steel-blue haired hind tibiae hang down 
when on the wing, just like the Pompilidae do with their prolonged legs. — The Cameroon Aegeriid Crypto- 
mima harnpsoni (77 h) exhibits, as another mark of resemblance to Aculeates, a fictitious sting of 2 cm length. 
The distribution of the Aegeriidae is quite universal, and it is to be considered a fact that the part 
they are playing in the household of Nature is generally depreciated on account of their discovery being so 
difficult. The great frequency of their larvae even with species, such as the Bembecia, whose imagines are 
hardly ever discovered in free nature even by expert collectors, gives us an idea of the great seclusion in which 
these insects live. It is only when collecting Hymenoptera with eagerness and experienced knowledge that 
we recognize in what numbers at least some species occur. In North Africa I succeeded in capturing, in one 
forenoon, more than 20 specimens of 5 species, and in the Itatiaya Mts. I was able to capture Aegeriidae almost 
every day and once I fetched, with one blow of the net, 4 specimens from the blossoms. Otherwise, however, 
the Aegeriidae are all, except very few species, very rarely met with. Moreover, it must be considered that the 
time for observing other diurnal lepidoptera begins with their swarming time, whereas here with the Aegeriidae 
it usually stops with the breaking of the flying hour, because they then submerge amidst the confusing multitude 
of their models. This behaviour of the tropical Aegeriidae is quite similar to that of the palaearctic Aegeria\ 
if one omits collecting them on the trunks where they emerge early in the morning before they fly away, it is 
difficult to capture any number worth mentioning. 
Nearly all the Aegeriidae love flowers and are not dainty in the kind of their food. They also like to 
go to baits, and in wasp-traps which are set for destroying the wasps we almost regularly find drowned 
Aegeriidae in the flying time. Apparently relying on their Aculeata exterior they mostly remain on the blossom 
from which they suckle the honey, and it is then very easy to approach them. The Synanthedon can mostly 
be taken from the blossoms with the glass or the hand; only when they rest shortly on leaves, or in swarming 
itself they fly off in a very dexterous way and are difficult to pursue, and once being scared away they generally 
do not return. The flight of the lighter species is swift and restless, usually very much influenced by the habits 
of the model. The Aegeria resembling the yellow plait-wasps fly straight on and somewhat clumsily, like stout 
V espa-Q. The Synanthedon recalling Ichneumonides use to make quick oscillating movements before settling 
down, in the same way as we see it done by the ichneumons which they resemble. The Melittia exhibit a 
searching swarming flight like that of bees collecting honey. The Aegeriidae seem not to fly continuously, for 
when they are wandering on mountain-slopes, meadows, or along hedges, they make a halt for a while on leaves 
and stalks after short flights. 
Like many smaller though fugitive lepidoptera the Aegeriidae are likewise very generally and uniformly 
distributed over the globe. They are to be found in all the faunae; nowhere in crowds, often even very rarely, 
but nowhere absent—excepting the cold zones. So far it might appear that the tropics are less abundant in 
species than the temperate zones, just like in the other lepidopteral families; but the reason for this is un¬ 
doubtedly the fact that the temperate zones have been well searched, whilst the tropics will probably produce 
yet a considerably large number of hitherto undiscovered species. It is just from the Ethiopian region where 
the vast dry and sunny steppes are particularly favourable for the development of great numbers of Aegeriidae 
that we may expect yet especially many new forms. 
Of the almost 1000 forms hitherto known one fifth occur in the Ethiopian, one fifth in the Indo-Australian, 
two fifths in the American, and the rest in the palaearctic region. 
