Belongs within: Psocinae.
Psocus is a genus historically used to cover a wide range of (if not all) barklice, now restricted to a more narrowly defined group found in the Holarctic realm and Africa. The type species P. bipunctatus is characterised by the presence of a submedian free sclerotised rod in the hypandrium, and a large, almost circular external valve on the gonapophyses (Lienhard 1998).
Characters (from Mockford 1993): Adults of both sexes macropterous. Nine distal inner labral sensilla. Fore wing marking with pterostigma with brown spot, very variable in size, likewise stigmasaum; a brown mark associated with M-Cu1 branching point; a brown spot at nodules. Hypandrium lacking basal sclerites; with broad median strap bending upward distally and bearing basal tooth or lobe. Phallosome somewhat tapering and rounded anteriorly or with short anterior apodeme; distally variable. Male epiproct flat, not extending anteriorly over clunium; clunium extending at least slightly over epiproct in middle. Male paraproct with shoulder lateral to distal process. Subgenital plate with distal process relatively long and slender; pigmented arms directed posterolaterally, bearing a shallow to moderate trench and row of setae along their length; arms expanded distally. Ovipositor valvulae with apical process of v2 short; v3 large, rounded or quadrate, with median lobe short to moderate.
<==Psocus Latreille 1794 [=Psochus Latreille 1796]L02 |--*P. bipunctatus (Linnaeus 1761)L98 (see below for synonymy) |--P. alticolus Banks 1937NL07 |--P. annulipes Reuter 1899 (n. d.) [=Psocidus annulipes]L98 |--P. capitatus Okamoto 1907L02 |--P. ciliatus Latreille 1795L95 |--P. crosbyi Chapman 1930M93 |--P. dolorosus Banks 1937NL07 |--P. formosanus Okamoto 1907L02 |--P. funerulus Costa 1885 (n. d.) [=Psocidus funerulus]L98 |--P. grisescens Mc. Lachl. 1866E07 |--P. illotus Banks 1939NL07 |--P. incomptus Banks 1937NL07 |--P. jeanneli Badonnel 1945L98 |--P. kiboschoensis Enderlein 1907E07 |--P. kolbei (Enderlein 1906)L02 |--P. lapidarius Badonnel 1936L98 |--P. leidyi Aaron 1886 [incl. P. bilobatus Banks 1918]M93 |--P. mucronicaudatus Li 2002L02 |--P. omissus Banks 1939NL07 |--P. rizali Banks 1939NL07 |--P. sjoestedti Enderlein 1907E07 |--P. socialis Li 1997L02 |--P. striatulusL95 `--P. vannivalvulus Li 1995L02
*Psocus bipunctatus (Linnaeus 1761)L98 [=Hemerobius bipunctatusL02; incl. P. bipunctatus var. grisescens Tetens 1891 non Mc. Lachl. 1866L98, P. bipunctatus var. spaengbergi Kolbe 1880G74]
*Type species of generic name indicated
References
[E07] Enderlein, G. 1907. Wissenschaftliche Ergebnisse der Schwedischen Zoologischen Expedition nach dem Kilimandjaro, dem Meru und den Umgebenden Massaisteppen Deutsch-Ostafrikas 1905–1906 vol. 15. Corrodentia pt 2. Copeognatha. Almqvist & Wiksells Boktryckeri-A. B.: Uppsala.
[G74] Günther, K. K. 1974. Staubläuse, Psocoptera. Die Tierwelt Deutschlands 61: 1–315.
[L95] Latreille, P. A. 1795. Extrait d’un mémoire pour servir de suite à l’histoire des termès, ou fourmis blanches. Bulletin de la Société Philomatique, a ses Correspondans 41–42: 1–3.
[L02] Li F. 2002. Psocoptera of China vol. 2. Science Press: Beijing.
[L98] Lienhard, C. 1998. Faune de France. France et Régions Limitrophes. 83. Psocoptères Euro-Méditerranéens. Fédération Française des Sociétés de Sciences Naturelles: Paris.
[M93] Mockford, E. L. 1993. North American Psocoptera (Insecta). Sandhill Crane Press, Inc.
[NL07] New, T. R., & C. Lienhard. 2007. The Psocoptera of Tropical South-east Asia. Brill: Leiden.