† Pyrenicocephalus jarzembowskii, gen. et sp. n. (Hemiptera: Heteroptera: Enicocephalomorpha: Enicocephalidae: Enicocephalinae) from Early Eocene, London Clay, England, Isle of Sheppey, is described and illustrated according to the unique pyritized adult head reported as a larval enicocephalid head by Jarzembowski (1986). The head anatomy of similar and related genera of Enicocephalinae is compared and the close relationship of the new genus to a clade including the extant genera Oncylocotis, Embolorrhinus and Hoplitocoris is suggested, most probably as the sister genus to Hoplitocoris (presently with Afrotropical, East Palaearctic and Oriental range).
Frenae are forewing-holding ridges situated in the Heteroptera parallel to the lateral sides of mesoscutellum, and covered by a squamiform, overlapping, glabrous microsculpture. The situation found in Rectilamina sp. (Dipsocoromorpha: Schizopteridae: Hypselosomatinae) suggests that each single squamiform element is homologous to a strongly modified microtrichium, and that, at least in this case, there is no basic difference between microtrichium and acanthus.