A staff member presents silkworm cocoons at a collecting station in Hai'an City, east China's Jiangsu Province, June 2, 2018. Hai'an is known for its silk cocoon industry. (Xinhua/Xu Jinbai)

Staff members carry silkworm cocoons at a collecting station in Hai'an City, east China's Jiangsu Province, June 2, 2018. Hai'an is known for its silk cocoon industry. (Xinhua/Gu Huaxia)

A staff member works with silkworm cocoons at a collecting station in Hai'an City, east China's Jiangsu Province, June 2, 2018. Hai'an is known for its silk cocoon industry. (Xinhua/Gu Huaxia)

Staff members sort silkworm cocoons by their quality at a collecting station in Hai'an City, east China's Jiangsu Province, June 2, 2018. Hai'an is known for its silk cocoon industry. (Xinhua/Xu Jinbai)

Staff members sort silkworm cocoons by their quality at a collecting station in Hai'an City, east China's Jiangsu Province, June 2, 2018. Hai'an is known for its silk cocoon industry. (Xinhua/Xu Jinbai)