Lice and barkflies (Psocodea)
The order Psocodea has historically been treated as two sister orders, Phthiraptera (sucking and biting lice) and Psocoptera (booklice and barklice). The treatment of both within the single order Psocodea appears to be consistent wtih the UKSI, although the RES wesbite still treats Phthiraptera and Psocoptera as separate orders, so I'm not sure if this change is universally accepted.
My experience of Phthiraptera is limited to the Head Lice Pediculus humanus removed from my scalp when I was an infant. Psocoptera are separated into two groups, the booklice (mainly found indoors) and barklice (usually found outdoors), the latter often known as barkflies. So far I've only recorded a few species of barkfly, most of which I am yet to add to this site.
I use the RES Handbook to Psocids by T R New (2nd edition, 2005) which is really good, but I tend to turn to the online National Barkfly Recording Scheme key first. Beware if using New that there is at least one now-common recently introduced species that does not feature there (Chilenocaecilius ornatipennis).
Family Paracaeciliidae
includes genus Chilenocaecilius
Family Caeciliusidae
includes genera Enderleinella, Epicaecilius and Valenzuela
Family Stenopsocidae
includes genera Graphopsocus and Stenopsocus
Family Lachesillidae
includes genus Lachesilla
I am in the process of working through these systematically, but have only covered the species shown above so far. The following were previously added here on an ad hoc basis.
Ectopsocus briggsi
Ectopsocus petersi
Peripsocus milleri
Trichopsocus brincki
Philotarsus parviceps
Elipsocus abdominalis (?)
Loensia fasciata