PuU. 8. VII. 1924. 
BOMBYCIDAE. General Topics. By Dr. A. Seitz. 
433 
11. Family: Bombycidae. 
This group, as it was hitherto comprehended, and arranged in Kirby’s Catalogue, only contains about 
60 to 80 forms, 16 of which occur in the palearctic region (where they were partly introduced), whilst about 
50 occur in the Indo-Australian region and but very few in the Ethiopian region. To what extent the American 
forms (about 50) reckoned to the Bombycidae are allied with the Indian Bombycids will be discussed when 
dealing with them; they are undoubtedly less allied to all the palearctic forms than the latter are to each other. 
The principal characteristica are the stunted stomatic parts. Not only the whole proboscis is entirely 
absent, but also of the palpi there are merely atrophous remainders entirely hidden in the wool of the face. In 
this respect they differ particularly from the Brahmaeids to the larvae of which they are otherwise somewhat 
similar. The antennae are (like in the Brahmaea) also in the $ bi-combed and exhibit rather strong small branches. 
The reason of this may be that most of the Bombycidae are rather monophagous and that therefore also the 
$$ require a well developed sense of smelling in order to detect the food-plant. 
In Vol. II (p. 189) we have already called the readers’ attention to the peculiarly bent-over apex of 
the forewing, being a distortion by which the branches of the subcostal vein appear to be bent down. The 
discal cell, especially on the forewing, is considerably larger than in the Eupterotids from which the Bom¬ 
bycids differ besides by the presence of a frenulum. 
The larvae, however, differ entirely from those of the Eupterotids which are densely covered with long 
hair, whereas the Bombycidae are almost entirely without it. Though — especially in the early stage — there are 
traces of a hairy cover, it becomes atrophous later on and even entirely bare, like in the Brahmaea and the 
American Ceratocampids. Like in the latter, also in the Bombycidae the body grows into protuberances 
or cones, which may in some cases produce a horny caudal formation being peculiar of the habitus of the Sphingid 
larvae. 
The pupa the shape of which does not show any peculiarities, rests in a cocoon the industrial utiliza¬ 
tion of which by the silk-spinner has become of world-wide importance. Beside certain Saturniids and the Lasio- 
campid Pachypasa otus (comp. Vol. II, p. 174), the Bombycid Bombyx mori is the chief producer of silk and 
excels the former considerably in their importance. This is the reason why such a great number of artificial 
races were cross-bred from Bombyx mori as in no other insect. 
The 33 of the Bombycids, except Bombyx mori having been modified by domestication, are good 
flyers which, however, only move about at night and are very much attracted by the light. In daytime the 
brown species mostly rest on the trunks of the food-trees, wfhereas the white ones lie flatly spread on the 
leaves, some exhibiting a somewhat distorted position: they press their forehead on the base and turn their 
abdomen upwards. They place their wings above each other in such a way that the proximal margin of the 
hindwing looks out from beneath the forewing, which usually also influences the colouring of the inner-marginal 
area of the hindwing. 
The larvae seem to live rather exclusively on trees and frequently prefer cultivated trees (such as figs, 
mulberries). In Eastern Asia the Bombycidae are often found in towns and avenues and are preferably developed 
on shady trees in the gardens and streets. 
As we have already mentioned the typical species, on which the family was founded, has an economical 
importance such as no other insect, not even the honey-bees. The history of the s i 1 k - m o t h is so closely 
associated with the history of humanity that neither can be separated from the other. Already for the time 
in which the world’s history passes over from myths and uncontrollable traditions to historical facts, the produc¬ 
tion of silk is mentioned. The Chinese — the Seres of the ancient occidental nations — attribute the discovery 
of the silk webs to the reign of the mythical Emperor Hwang-ti, but the secretion of the silk-glands of 
Bombyx mori was differently applied already before that time, for strings for a kind of guitarre, and for fishing- 
lines, which are up to this day yet manufactured in China from the spinning secretion of the Saturniid Eriogyna 
pyrelorum (Vol. II, t. 31 a). In this latter application the silk is already mentioned from the year 3000 when, 
according to the well-known Chinese historical work ,,Shu-king“. the Emperor Shin created mulberry-plantations 
in order to encourage the manufacture of fishing-lines. 
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