Abstract Background At the turn of the 19th century the first observations of a female-biased sex ratio in broods and populations of the head louse. Pediculus humanus capitis. had been reported. A study by Buxton in 1940 on the sex ratio of lice on prisoners in Ceylon is still today the subject of reanalyses. https://www.markymarkscott.com/product-category/hair-mask/