CARAPHRACTUS Walker, 1846

(Figs 246–273)

Caraphractus Walker, 1846: 49 (key), 50 (description). Type species: Caraphractus cinctus Walker, 1846, by monotypy. Valkerella Westwood, 1879: 584 (footnote). Type species: Polynema natans Lubbock, 1864, by monotypy.

Walkerella Dalla Torre, 1898: 425 . Unjustified emendation.

Diagnosis. Body length 795–1250 μm. Head, mesosoma, petiole and coxae heavily sculptured with isodiametric reticulations (Figs 246–250, 253, 254); antenna with clava 1-segmented and widening towards apex (Fig. 252); fore wing with 1 distal macrochaeta, apparently without marginal vein, and with parastigmal and stigmal veins together as long as submarginal vein (Fig. 251).

Discussion. Among the nine other Nearctic genera of the Polynema group ( Acmopolynema, Cnecomymar, Eustochus, Kalopolynema, Mymar, Neomymar, Palaeoneura, Polynema, Stephanodes), Caraphractus is the sister genus to Eustochus . Together they form a distinct subgroup distinguished by their heavily sculptured head, mesosoma, and petiole.

Nearctic hosts. Coleoptera: Dytiscidae .

Important reference. Triapitsyn (2011a).