Aclerda, Signoret, 1874

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 : 213-215

Aclerda sp. B ( Fig. 83 )

Material examined. USA, South Dakota, Pennington Co., Wasta, on grass ( Poaceae ), 12.viii.1970, D.R. Miller #1841 ( USNM): 1/1 ad ♂ (in good condition).

Mounted material: total body length 1.27 mm; width across triangular plates 0.23 mm; very slender. With small convex pores (cp) on thorax and abdomen.

Head: approximately diamond-shaped in dorsal view; proportionately rather long, length 190 μm; width across genae 185 μm. Median crest (mc) not reticulated at anterior end but with a broad area of reticulation posteriorly; with 1 hs dorsal head seta (dhs) on each side anteriorly and 1 pair hs posteriorly. Dorsal mid-cranial ridge absent; ventral mid-cranial ridge (vmcr) represented by a short sclerotised mid-cranial ridge, with a short arm extending towards each scape; ventral mid-cranial ridge with a narrow, slightly reticulated border and a broader area of slight sclerotisation immediately posterior to each scape, which extends posteriorly to ocular sclerite; with 1 hs ventral mid-cranial ridge seta (vmcrs) on each side. Genae: genal setae (gs) 1 hs posterior to each dorsal eye. Eyes: two pairs of unusually small, round, simple eyes, subequal in size (each 15–17 μm wide). Ocelli (o) not detected. Ocular sclerite (ocs) polygonally reticulated, without inner microridges. Preocular ridge (procr) present, represented by a very short sclerotised ridge immediately posterior to each scape ventrally. Postocular ridge (pocr) short and not heavily sclerotised. Dorsal ocular setae (docs) absent. Ventral head setae (vhs): 1 or 2 hs just posterior to each scape. Cranial apophysis (ca) 121 μm anterior to tentorial bridge; with numerous short digitations apically.

Antennae: rather short, total length 589 μm long (ratio of total body length to antennal length 1:0.46). Scape (scp): 35–37 μm long, 43–47 μm wide; with 1 hs on ventral surface and 2 hs on dorsal surface. Pedicel (pdc): length 27–31 μm, width 35–39 μm; with 1 or 2 hs (no sensilla placodeum detected). Segments III–X all 16–21 μm wide: fs each 23–28 μm long; lengths of segments (μm): III 65–70; IV 77–83; V 66–70; VI 69–75; VII 69–84; VIII 59 and IX 52–59; setae rather few, approximate number per segment: III 1 fs + 3 hs + 2 sensilla basiconica; IV 8–10 fs + 2 or 3 hs; V 7 or 8 fs + 0 or 1 hs; VI 7–10 fs + 0 hs; VII 8–13 fs + 0 hs; VIII 8 or 9 fs + 0 hs; IX 7–9 fs + 0 hs. Segment X 57–65 μm long, with 8–10 fs (including bristles, latter barely if at all differentiated) + 3 capitate setae.

Thorax. Prothorax: pronotal ridge (prnr) well-developed and probably fusing medially; lateral pronotal sclerite (prn) probably absent. Medial pronotal setae, post-tergites and post-tergital setae apparently absent, but with a group of 4–9 convex pores (cp) on each side just posterior to pronotal ridge dorsally. Sternum (stn 1) sclerotised, but without either a median or a transverse ridge; without reticulations; with 1 hs prosternal seta (stn 1 s) on each side. Anteprosternal (astn 1 s) and antemesospiracular setae (am 2 s) absent.

Mesothorax: prescutum (prsc) 105 μm wide, 47 μm long; prescutal ridges (pscr) and prescutal suture (pscs) well developed; prescutal setae absent. Scutum (sct): median membranous area 78 μm wide, 22 μm long, bounded laterally by a weakly sclerotised margin; with 1 hs scutal seta (scts) on each side; reticulations weak or absent laterad to scutellum. Scutellum (scl) 96 μm wide, 34 μm long; with a small foramen; with 1 pair hs scutellar setae. Basi- sternum (stn 2) particularly small, about 108 μm wide, 71 μm long; median ridge (mdr) absent; bounded anteriorly by a weak marginal ridge (mr) and posteriorly by a strong precoxal ridge (pcr 2); without basisternal setae (stn 2 s); lateropleurite proportionately very large, without an extension along anterior margin from marginal ridge; furca nearly reaching marginal ridge anteriorly. Area bounded anteriorly by scutellum and laterally and posteriorly by mesopostnotum lightly sclerotised with a narrow membranous area along anterior and lateral margins. Mesepisternum (eps 2) and subepisternal ridge (ser) well developed. Postalare (pa) not reticulated anteriorly; without postalare setae (pas). Postmesospiracular setae (pm 2 s) absent. Mesothoracic spiracle (sp 2): peritreme 24–27 μm wide, each with 3 or 4 disc-pores. Tegula (teg) with 2 hs tegular setae (tegs) on each side.

Metathorax: with 1 pair metatergal setae (mts) plus 4 small convex pores (cp) on each side. Dorsospiracular setae (dss) absent. Dorsal part of metapleural ridge (plr 3) absent; ventral part of metapleural ridge not well developed; metepisternum (eps 3): small area sclerotised near metapleural ridge; without postmetaspiracular setae (eps 3 s). Metepimeron (epm 3) absent, without setae. Antemetaspiracular setae (am 3 s) absent. Metathoracic spiracle (sp 3): width of peritreme 27–29 μm, each with 1 disc-pore. Postnotal apophysis (pna) represented by a narrow, reticulated slit between meso- (pn 2) and metapostnotum (pn 3). Metasternum (stn 3) lightly sclerotised. Anterior (amss) and posterior metasternal setae (pmss) absent.

Wings: proportionately small and very narrow, about 719 μm long and perhaps 186 μm wide (ratio of length to width 1:0.26; ratio of total body length to wing length 1:0.57); without alar lobes and alar setae. Hamulohalteres absent.

Legs: legs proportionately short; subequal in length. Coxae (cx): I 77–79; II 83–85; III 77–79 μm long; coxa III with about 8 hs (2 long, each about 70 μm long). Trochanter (tr) + femur (fm): I 189; II 182–184; III 170–172 μm long; trochanter III with 3 hs; long trochanter seta short: each 18–21 μm, flagellate; femur III with about 0 fs + 23 hs. Tibia (ti): I 173–175; II & III each 176–178 μm long; tibia III with a total of about 19 setae, mostly spurlike, particularly on distal third of leg; apical spur (tibs) (III) 10–12 μm long. Tarsi (ta): I 99–100; II 87; III 80–82 μm long (ratio of length of tibia III to tarsus III 1:0.46); tarsus III with 16 setae, mostly spur-like; tarsal spurs (tabs) absent or not differentiated; tarsal digitules capitate. Claws (c) (III) 26 μm long, without a denticle; claw digitules capitate.

Abdomen: tergites (at) and sternites (as) sclerotised on all segments; pleurites (ap) sclerotised only on segments IV–VII, each including some sclerotisation around ventral pleural setae. Dorsal abdominal setae (ads) (on each side): segments I–III each with 1 hs + 2 or 3 convex pores (cp); IV–VII each with 1 hs + 1 or 2 dp. Pleural setae (on each side): dorsopleural setae (dps) II–VII each with 0–2 hs + 1–3 dp; ventropleural setae (vps) II–VII each with 1 hs. Ventral abdominal setae (avs) (totals): II 0 hs; III 2 hs; IV–VII each with 4 hs. Caudal extensions on segment VII rounded.

Segment VIII tergite with 1 pair hs dorsal abdominal setae (ads); sternite forming a sclerotised plate, with a strongly sclerotised lateral margin; without a caudal extension but with 3 or 4 hs longer pleural setae, one of them 60+ μm long. Glandular pouches absent.

Genital segments: penial sheath (ps) articulating anteriorly with sternite of segment VIII; length 169 μm long including sclerotised part of segment VIII; segment IX 74 μm wide at swollen base (ratio of total body length to penial sheath length 1:0.13). Anus (an) surrounded by a sclerotised ring. Style broad anteriorly, narrowing to a blunt apex. Basal rod (bra) short, 23 μm long. Aedeagus (aed) short, about 40 μm long (ratio of aedeagus length to basal rod length about 1:0.58); approximately parallel-sided but broader than apex of style. Style with minute setae and sensilla throughout. Membranous ‘endophallus’ present.

Comment. Aclerda sp. B. differs from both A. arundinariae and Aclerda species A in (i) the narrowness of the mesothorax and the smallness of the basisternum; (ii) in the small size of the wings and limbs; (iii) in lacking postmetaspiracular setae, and (iv) in the presence of a broad area of reticulation medially on the dorsal surface of the head. It also differs from A. arundinariae in (i) possessing small convex pores on the dorsum of the thorax and abdomen, and (ii) in having abdominal pleurites extending ventrally to include the ventral pleural setae. It is similar to Aclerda sp. A, but the latter (i) is rather broader in the mesothorax (the basisternum is much larger) and the former has (ii) postmetaspiracular setae and (iii) a metepimeron.

Figures

FIGURE 83. Aclerda sp. B. South Dakota, USA. Macropterous male. (Aclerdidae, Aclerdinae). Where A=cranial apophysis, C=loculate pore, D=simple pore and R=dermal reticulations on ocular sclerite.