Aclerda tokionis Cockerell

Hodgson, Chris, 2020, A review of neococcid scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) based on the morphology of the adult males, Zootaxa 4765 (1), pp. 1-264 : 208-210

Aclerda tokionis Cockerell ( Fig. 81 )

Sphaerococcus (Pseudolecanium) tokionis Cockerell 1896b , 19. Type data: Japan, [presumably Tokyo] on twigs of bamboo; collected Takahashi. Syntypes, female. Type depository: USNM.

Pseudolecanium tokionis (Cockerell) ; Cockerell 1899b, 263. Change of combination.

Aclerda japonica Newstead 1901 , 84. Type data: England, Herts, Broxbourne, in greenhouse, on the leaf sheaths of Arundinaria japonica . Syntypes, female. Type depository: BMNH. Junior synonym, McConnell 1954, 99.

Aclerda tokionis (Cockerell) ; Cockerell 1902c, 453. Change of combination.

Material examined: Japan, Tokyo, on bamboo ( Poaceae ), no date, S.I. Kuwana ( BMNH): 1/2ad ♂♂ (one in good condition but lacking wings and antennae, other specimen rather poor).

Mounted material: total body length 1.35 mm; width across triangular plates 0.29 mm; slender.

Head: approximately diamond-shaped in dorsal view; approximate length 186 μm; width across genae 227 μm. Median crest (mc) not reticulated but with transverse striations; with 3 hs dorsal head setae (dhs) on each side anteriorly and a pair of hs posteriorly. Dorsal mid-cranial ridge absent; ventral mid-cranial ridge (vmcr) short between scapes, with short lateral branches; vmcr with a sclerotised, non-reticulated border, which extends posteriorly almost to ocular sclerite; with 3 or 4 hs ventral mid-cranial ridge setae (vmcrs). Genae: genal setae (gs) absent. Eyes: two pairs of rather small, oval, simple eyes, subequal in size (25–27 μm long, 18 μm wide). Ocelli (o) clearly present laterally. Ocular sclerite (ocs): polygonally reticulated only around simple eyes, each reticulation narrow. Preocular ridge (pocr) absent. Postocular ridge (pocr) well developed, extending to each ocellus but perhaps no further. Dorsal ocular setae (docs) absent. Ventral head setae (vhs): absent. Cranial apophysis (ca) 113 μm long anterior to tentorial bridge; apex well digitated.

Antennae: only scape and pedicel present. Scape (scp): 38–40 μm long, 48 μm wide, with 1 hs dorsally and 2 hs ventrally. Pedicel (pdc): length 43 μm, width 33–35 μm; with 1 fs, 2 hs + a sensilla placodeum. Segments III–X missing.

Thorax. Prothorax: pronotal ridge (prnr) not considered to be fused medially; pronotal sclerite (prn) probably present but narrow. Pronotal setae (stn 1 s), medial pronotal setae, post-tergites and post-tergital setae absent. Post- tergites (pt) present. Small convex pores (cp) absent. Prosternum (stn 1): mildly sclerotised, without either a median or a transverse ridge; without reticulations and without prosternal setae (stn 1 s). Anteprosternal (astn 1 s) and antemesospiracular seta (am 2 s) absent.

Mesothorax: prescutum (prsc) unusually small and heavily sclerotised, 312 μm wide, 62 μm long, with a strongly sclerotised median ridge; not reticulated; prescutal ridges (pscr) and prescutal suture (pscs) exceptionally well developed; without prescutal setae (prscs). Scutum (sct): median membranous area 107 μm wide, 29 μm long, with 1 hs scutal seta (scts) on each side. Scutellum (scl) 155–174 μm wide, 50 μm long; with a small foramen; without scutellar setae; posterior notal wing process (pnp) rather long. Mesopostnotum (pn 2): area bounded laterally by mesopostnotum and anteriorly by scutellum with a large sclerotised area surrounded anteriorly and laterally by a membranous area. Basisternum (stn 2) rather poorly developed and unusually small: about 170 μm wide, 83 μm long; median ridge (mdr) absent; marginal ridge absent but precoxal ridge (pcr 2) strong; with 2 hs basisternal setae (stn 3 s) laterally on each precoxal ridge. Lateropleurite very broad, without an extension from marginal ridge; furca (f) well developed, broad basally, arms more or less parallel and quite short. Postalare (pa) not reticulated anteriorly; without postalare setae (pas). Postnotal apophysis oval but not very elongate. Mesothoracic spiracle (sp 2): peritreme 23 μm wide, each with 2–6 disc-pores. Tegula (teg) with 1 or 2 hs tegular setae (tegs) + 1 disc-pore.

Metathorax: with 1 pair of metatergal setae (mts) + 3–6 small convex pores (cp). Dorsospiracular setae (dss) probably absent. Dorsal part of metapleural ridge (plr 3) absent; ventral part of metapleural ridge not well developed. Mepisternum (eps 3) with 4 hs postmetaspiracular setae (eps 3 s) on each side. Metepimeron present, without setae. Antemetaspiracular setae (am 3 s) absent. Metathoracic spiracle (sp 3): width of peritreme 23–27 μm; with 2–4 discpores. Postnotal apophysis (pna) represented by a narrow, reticulated slit between meso- (pn 2) and metapostnotum (pn 3). Metasternum: condition uncertain. Anterior (amss) and posterior metasternal setae (pmss) absent.

Wings: missing but clearly alate. Hamulohalteres absent.

Legs: prothoracic legs slightly longer than other legs; without pronounced concentric ridges. Coxae (cx): I 78–95; II 87; III 79 μm long; coxa III with about 0 fs + 4–6 hs (2 long setae on procoxae, each about 45 μm long; possibly absent on meso- and metacoxae). Trochanter (tr) + femur (fm): I 194–207; II 207; III 186 μm long; tro- chanter III with 2 hs; long trochanter seta: 93–117 μm, flagellate; femur III with about 17 hs. Tibia (ti): I 273–278; II 269; III 236 μm; all tibia heavily sclerotised along dorsal part, apparently unsclerotised along ventral part, each with 6–8 long, very spinose setae along ventral margin (each 26–30 μm long); in addition, tibia III with about 14 more or less spinose hs; without a sclerotised tibio-tarsal articulation; apical spur (tibs): length ( III) 18–23 μm. Tarsi (ta): I 107–112; II 104; III 95 μm long (ratio of length of tibia III to tarsus III 1:0.35); tarsus III with 3 very spinose setae + about 19 other setae, mostly spur-like; tarsal spurs (tabs) absent or barely differentiated; tarsal digitules all missing. Claws (c): length ( III) 23 μm; without a denticle; claw digitules capitate.

Abdomen: tergites (at) and sternites (as) sclerotised on all segments; pleurites (ap) sclerotised only on segments IV–VII, extending medially to include ventral pleural setae. Dorsal abdominal setae (ads) (totals): segments I–VII each with 2 hs, plus 2–4 dp on each side. Pleural setae: (on each side): dorsopleural setae (dps): II & III each with 1 hs; IV–VI each with 3–5 hs; VII 7 hs; ventropleural setae (vps) II 0 hs; III–VII each with 1 hs. Ventral abdominal setae (avs): II 0 hs; III & IV both with 1 or 2 hs; V–VII each with 3–6 hs. Caudal extensions on segment VII rounded.

Segment VIII with a strongly sclerotised sternite, quite long, 70 μm wide, 83 μm long. Caudal extension absent but with a group of 3 or 4 hs pleural setae, all short, no long setae present.

Genital segments: segment IX articulating anteriorly with sternite of segment VIII; total length 223 μm, includ- ing sclerotised part of segment VIII (ratio of total body length to penial sheath length 1:0.17); segment IX slightly narrower than sternite VIII. Anus (an) surrounded by a sclerotised ring. Style fairly long, parallel-sided anteriorly, narrowing to a blunt apex. Basal rod (bra) short, 48 μm long. Aedeagus (aed) short, 50 μm long (ratio of aedeagus length to basal rod length 1:0.96), broader than apex of style but not reaching apex of style. Penial sheath with about 20 small setae on each side. Membranous endophallus absent.

Comment. A. tokionis is very similar to the other species described here, but differs mainly in the structure of the thorax, which has a rather small, heavily sclerotised prescutum with a strong median ridge and with a rather narrow, poorly developed basisternum, without an anterior marginal ridge. It also lacks a pair of long setae on abdominal segment VIII.

Figures

FIGURE 81. Aclerda tokionis Cockerell. Macropterous male. (Aclerdidae, Aclerdinae). Where A=cranial apophysis.