Genus Pleioplectron. Hutton, 1897

• 1897. Pleioplectron Hutton, Trans. N.Z. Inst., 29: 232–233.

• 1899. Miotopus Hutton, Trans. N.Z. Inst., 31: 41.

In 1897, Hutton erected the genus Pleioplectron and placed in it four new species, Pleioplectron simplex, P. hudsoni, P. pectinatum and P. diversum. Two years later he added Macropathus edwardsii (Scudder) to the genus as P. edwardsii (Scudder), and placed P. diversum in a new genus as Miotopus diversum (Hutton). In 1900, he described a new species as P. cavernae.. Finally, in 1904, he added a new species from the Chatham Islands as P. serratum. This species has been placed in a new genus by the author as Novoplectron serratum (Hutton) (Richards, 1958a).

Hutton's original material of the type species for the genus has been examined by the author, and has been found to differ from Hutton's generic description. He described the fastigium as sulcate instead of convex. He says the hind femora are without apical spines, when they possess a prolateral apical spine beneath. According to Hutton, the hind tibiae are armed with three pairs of apical spines, while re-examination shows they possess four pairs. His description of the genitalia is also inaccurate. He describes the supra-anal plate of the male as “transverse, the apex truncated, with a small point in the middle”, whereas it is trilobed, the two outer lobes each tapering to a point, while the median lobe is rounded. The subgenital plate of the male he describes as “longer than broad, cuspidate, terminating in an acute point between the styles” when it is subequal in length to width, trilobed distally, with the median lobe pointed and strongly keeled. Of the subgenital plate of the female he says, “apex with three points”. While this is the case in P. diversum, in P. simplex, the type species for the genus, it is produced into two rounded lobes separated by a widely emarginate area.

Transactions of the Royal Society of New Zealand Vol. 87, Parts 3 and 4, pp. 319–327, 3 Text-figs, November, 1959

The genus Pleioplectron Hutton therefore must now be redefined as follows:—

Body clothed with numerous short setae. Legs long and slender. Antennae very long and tapering, almost touching at their bases; scape about four times as large as pedicel, which is narrower than scape, but broader than other segments; from fourth segment onwards segments subequal, although steadily decreasing in size; all segments thickly clothed with short setae. A single anterior, median ocellus only. Fastigium rising abruptly, convex, ridged medianly and longitudinally. Maxillary palps with third and fourth segments subequal in length. All femora sulcate ventrally. No linear spines occur on fore or middle femora and tarsi. Apical spines on femora, tibiae, first and second proximal segments of hind tarsi constant in number. Fore femur bears one apical spine beneath prolaterally; fore tibia bears four apical spines, one above and one beneath both prolaterally and retrolaterally; fore tarsus unarmed. Middle femur bears two apical spines beneath, one prolateral and the other retro-lateral; middle tibia bears four apical spines, one above and one beneath, both prolaterally and retrolaterally; middle tarsus unarmed. Hind femur bears one apical spine beneath prolaterally; hind tibia bears a pair of long apical spurs above, a pair of subapical spines above, a pair of short apical spurs beneath and a pair of subapical spines beneath, one from each pair being prolateral and the other retrolateral; two proximal segments of hind tarsus each bear two apical spines above, one prolateral and one retrolateral; other two segments unarmed. Subgenital plate of female two or three-lobed. Subgenital plate of male trilobed distally, the median lobe being keeled. Latero-medianly the plate bears two styli, one to each side.

Type species for the genus: Pleioplectron simplex Hutton.