The genus Giropus lives amidst the fur of the Guinea pig, and sometimes literally swarms in places about their neck and ears.

The species are yellowish, marked with chestnut brown, especially upon the head, thorax, and legs, and have a broad ovate or elliptical body, with the head lobate behind.

Much interest attaches to these little creatures, notwithstanding the disagreeable impression commonly produced by their presence upon our domestic pets.

They possess such an extraordinary gathering of structural variations, have so many peculiar modes of life, and often display such a marked degree of individuality, that they deserve to be carefully studied in order to become more accurately known.

During the life of their host, they know quite well how to evade the scrutiny of man, and they are often difficult to discover, even in regions of a birds plumage where they are known to exist.