|
Bombyx Linnaeus
Type species:
mori Linnaeus.
Synonym: Theophila Moore (type species mandarina Moore, China).
The taxon mandarina is thought to be the wild source of the cultivated silkworm,
B. mori (Miyata, 1970; Franclemont, 1973). The male genitalia, particularly the
structure of the eighth abdominal sternite, of the two taxa are very similar and
hence they are certainly congeneric, if not conspecific.
In the
wing venation the M stem is absent from the forewing cell, unlike in the next
genus and the Ocinara group. CuP is relatively much weaker than in those
genera, being obvious only towards the margin. The forewings are falcate, with a
slight angle at the centre of the margin.
The coloration is grey, with darker fasciae on both wings. The apex of the
forewing is broadly black, this area extending back to the central angle of the
margin and being bounded basally by a narrow pale band and the thin dark
submarginal fasciae. Sexual dimorphism is not pronounced.
The male genitalia have the saccus strong, the valves long and narrow, the
gnathus heavily sclerotised, entire, and the uncus similarly sclerotised,
bilobed.
The female genitalia (mori/mandarina) have the eighth segment large, with a
posteriorly directed, marginally dentate heavily sclerotised plate arising from
the lamella post-vaginalis; a similar but less heavily dentate or sclerotised
plate arises from the lamella antevaginalis; the margin of the eighth sternite
is similar.
The larva of mori is very variable in colour; the thoracic zone is swollen and
the caudal horn reduced to a hump. In B. mandarina the horn, though short, is
present, and the colour patterning is more striking and contrasted. It is
illustrated by Miyata (1970). The larva of the Bornean species may resemble that
of huttoni as described below. B. mandarina and B. mori both feed most commonly
on Morus, but Miyata has also noted the former from Malus (Rosaceae) and
Diospyros (Ebenaceae) in Japan. The cocoon of mandarina is rather loose and
irregular so considerable selection must have occurred over the years to yield
the neat, tightly woven cocoon of mori.
<<Back
>>Forward <<Return
to Contents page
|
