Wikipedia
Proctophyllodidae
The Proctophyllodidae are a family of the Acarina ( mite) order Astigmata. They contain many feather mites. The Alloptidae and Trouessartiidae were in earlier times included here as subfamilies.
Proctophyllodidae females are extremely similar among species and sometimes even hard to assign to a genus, while males vary much more. Two subfamilies are generally recognized, the Proctophyllodinae and the Pterodectinae. The main difference is that the female pregenital apodeme and epimerites IV are separated, while in the latter they are connected and form a distinct structure.