Platylomalus kusuii: Ohara, 1994, 190.

Japanese name: Ogasawara-chibi-hirata-emma-mushi.

Description. Body oblong, black and shining; femora, tarsi, mouthparts and antennae red brown. Body length, PPL, female, 2.09 - 2.60 mm (2.34 ± 0.08, n=6); PEL, male, 1.99 mm, female, 1.89 - 2.36 mm (2.11 ± 0.06, n=7). Width, male, 1.26 mm, female, 1.20 - 1.50 mm (1.35 ± 0.04, n=7). Biometric data are given in Table 35.

Frontal stria of head clearly impressed and complete; disk of head sparsely and finely punctate, the punctures being separated by two to five times their diameter.

Pronotal sides (Fig. 110A) slightly arcuate and convergent to apical fourth, thence strongly convergent to apices. Emarginated portion of apical margin bisinuate behind neck. Marginal pronotal stria complete, but shortly interrupted at middle on anterior margin. Disk of pronotum densely clothed with microscopic punctures, which become sparser and coarser on lateral third and are separated by two to three times their diameter. Antiscutellum area with a large puncture.

Epipleural marginal stria present on apical two-thirds. Elytral marginal stria deeply impressed, coarsely crenate and complete, its apical end extending along the apical margin of elytron and attaining to lateral three-fourths. Epipleura shining and sparsely clothed with fine punctures. Disk of elytra (Fig. 110A) sparsely covered with moderate punctures; the punctures separated by two or three times their diameter, becoming denser and finer on apical half narrowly along the suture, and becoming coarser broadly on apical third of elytron and narrowly around an oblique depression which is present on the laterobasal half of the elytron; the punctation around the oblique depression very large, round and deep; extreme apical band impunctate. Dorsal striae of elytron absent, but a rudimentary impression (2nd dorsal stria ?) present on apical two-thirds of lateral third and another (3rd ?) on basal half of lateral half.

Propygidium evenly and coarsely punctate, the punctures being separated by their own diameter to twice the diameter. Pygidium (Fig. 110C) densely clothed with fine punctures which are separated by their own diameter to twice the diameter. In female, pygidium with a punctation similar to that of the male and also with an irregular and liner sculpture (Fig. 110C).

Anterior margin of prosternal lobe (Fig. 110B) truncate; marginal stria of the lobe absent anteriorly and present laterally on median third; disk evenly covered with deep and moderate punctures which are separated by their own diameter to twice the diameter. Prosternal process completely with carinal striae, which are well impressed and feebly sinuate at middle, sometimes reduced basally; disk of the process sparsely clothed with fine punctures which are separated by two to four times their diameter. Descending lateral stria short and strongly carinate; outside area of the stria deeply depressed.

Anterior margin of mesosternum (Fig. 110B) feebly emarginate medially, its marginal stria absent anteriorly, and complete and well impressed laterally; the basal end of the stria hooked inwards; the apical end continued to metasternal stria; disk of the metasternum sparsely with fine punctures which are separated by three to five times their diameter, and with microscopic punctures sparsely intermingled. Meso-metasternal suture weakly impressed and feebly arcuate. Punctation of intercoxal disk of metasternum a little denser and finer than mesosternal ones, and the fine punctures being usually represented in pairs; lateral disk sparsely covered with large, round and shallow punctures, which become smaller and sparser; lateral metasternal stria deeply impressed, extending obliquely and outwardly, and reaching near the posterior coxal cavity; postmesocoxal stria well impressed, extending along basal margin and its lateral end strongly bent posteriorly.

Punctation of 1st abdominal sternum similar to that of metasternum, the punctures becoming coarser before apical angles; 1st abdominal stria complete on each lateral side.

Protibia with 4 denticles on outer margin. Metatibia with 5 spinules on outer margin, but the basalmost very small. Metatibia with 2 spinules near apex.

Male genitalia; as shown in Fig. 111A - K.

Female genitalia; as shown in Fig. 100L

Specimens examined. Holotype, Sakai-ura, Chichi-jima Is., 8/vi/1972, Y. Kusui leg. Paratypes: 1Åä, Nishi-ura, Haha-jima Is., 15/vi/1972, Y. Kusui leg.; 1Åâ3ÅäÅä, and 4 exs., Nakano-taira, Haha-jima Is., 29/vi/1976, Y. Kurosawa leg. (NSMT); 1 ex., Bonin Is., no date, M. Nishihara leg.; 1 ex., Bonin Is., vi/1969, T. Nakane leg.

Distribution. Japan (Ogasawara Isles.)

Remarks. Platylomalus kusuii can easily be distinguished by the characteristic large punctation on the humeral area of the elytra and the absence of a transverse stria on the mesosternum, in combination with its limited distribution (Ogasawara Isles.).

Table 35. Biometric data of Platylomalus kusuii M. Ôhara, sp. nov.

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Male (n=1) Female

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APW 0.61 0.59-0.71 (0.66± 0.02) 7

PPW 1.24 1.16-1.42 (1.28± 0.04) 7

PL 0.75 0.63-0.89 (0.76± 0.04) 7

EL 1.14 1.10-1.36 (1.23± 0.04) 7

EW 1.26 1.20-1.50 (1.35± 0.04) 7

ProW 0.63 0.61-0.75 (0.68± 0.02) 6

ProL 0.26 0.22-0.30 (0.25± 0.01) 6

PyL 0.32 0.22-0.32 (0.28± 0.01) 6

PTL 0.47 0.43-0.53 (0.49± 0.01) 7

MSTL 0.43 0.33-0.47 (0.43± 0.02) 7

MTTL 0.47 0.45-0.57 (0.52± 0.02) 7

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[Ogasawara Isles] Haha-jima: Mt. Chibusa-yama (1 ex., 15/vii/1991), T. Ueno.

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