Shen Collection, Middle Volume. Radical: Insect (chóng). Kangxi stroke count: 15. Page 1090, Entry 19.
Pronounced se.
Shuowen Jiezi (Explanation of Simple and Compound Characters): An insect that bites people.
Baopuzi (Master Who Embraces Simplicity): Lice grow on my body, yet I am not the parent of the lice, and the lice are not my descendants.
Huainanzi (Master of Huainan): When a great mansion is completed, swallows and sparrows congratulate one another. When the warm water for bathing is prepared, lice and nits lament together.
Book of Han (Qian Hanshu): The ox-fly, which can bite an ox, cannot deal with a tiny louse.
Also, sand louse. Guangya (Expanded Dictionary): The sand louse is the same as the yu creature. Bencao (Pharmacopoeia): It is found everywhere. If one steps on sandy ground on a clear morning or evening after rain, it will surely attach to the body, appearing like a hair, and once it pierces the skin, it burrows inside.
Also, cow louse, found on oxen. Also, pig louse. Zhuangzi: Those who live in opportunistic comfort are like lice on a pig. Also, dog louse. Poem by Han Yu: Gathering dog lice with sesame. Note: The lingma mentioned is what is currently known as sesame; its shape resembles a dog louse. Bencao says: It is also called dog louse.
Jiyun (Collection of Rhymes): Also written as a variant.
Ganlu Zishu (Manual of Characters for Civil Service): Commonly written as the variant.
Liushu Zhenge (Errors in the Six Scripts): Composed of the element for insect and the element for swift. The latter represents the character xun, indicating speed. The louse crawls quickly, thus it is an ideographic character. Writing it as the common variant is incorrect.