Cosmopterix phyllostachysea is a moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 of the Cosmopterigidae

Cosmopterigidae

Cosmopterigidae is a family of insects in the Lepidoptera order. These are small moths with narrow wings whose tiny larvae feed internally on the leaves, seeds, stems, etc of their host plants. There are about 1,500 described species...

 family. It is known from China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 (Jiangxi) and Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

.

The length of the forewings is about 6 mm.

The larvae have been recorded feeding on Poaceae

Poaceae

The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

 species in China and on Phyllostachys bambusoides in Japan. They leaf miner|mine the leaves of their host plant. The mine has the form of a linear-blotch mine. The linear starts small, but gradually widens. The last instar larvae create an oval chamber. It later makes a smaller overwintering chamber of silk-like fiber within this bigger chamber. After overwintering, the larvae begin feeding on the mesophyll in March.