1. Of certain silkworms: producing two broods per annum.
2. There are multivoltines.

Some species produce one, two, three, four, six, or even eight broods per annum, and in the commercial world are distinguished as, univoltines, bivoltins, trivoltins, quadrivoltins, etc.

1. Of the nature of silkworms.
2. Bombycidae is a family of broad robust moths (lepidoptera) from Asia that comprises about 100 species, including the domesticated silkworm that no longer exists in the wild; commercial silk is derived from the pupal cocoon.

1. Of certain silkworms: producing one brood per annum.
2. There are multivoltines.

Some species produce one, two, three, four, six, or even eight broods per annum, and in the commercial world are distinguished as, univoltines, bivoltins, trivoltins, quadrivoltins, etc.