Bombyx mori silkworms for the production of raw silk, has been under way for at least 5,000 years in China, from where it spread to India, Korea, Japan, and the West. The silkworm was domesticated from the wild silkmoth "Bombyx mandarina", which has a range from northern India to northern China, Korea, Japan, and the far eastern regions of Russia. The domesticated silkworm derives from Chinese rather than Japanese or Korean stock. Silkworms were unlikely to have been domestically bred before the Neolithic age. Before then, the tools to manufacture quantities of silk thread had not been developed. The domesticated "B. mori"
Crustacean larva post-larva is characterised by the use of abdominal appendages (pleopods) for propulsion. The post-larva is usually similar to the adult form, and so many names have been erected for the stage in different groups. William Elford Leach erected the genus "Megalopa" in 1813 for a post-larval crab; a shrimp post-larva is called a "parva"; hermit crab post-larva are called "glaucothoe". In the Branchiopoda, the most basal group of crustaceans, there is no metamorphosis; instead, the animal grows through a series of moults, with each moult adding various numbers of segments to the body, but without any dramatic changes in form.