Cystococcus Fuller, 1897

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 : 83-84

Cystococcus Fuller, 1897

Cystococcus Fuller 1897, 1346 . Type species: Cystococcus echiniformis Fuller by monotypy.

Introduction. This genus was considered by Cockerell (1902b), Fernald (1903) and Hoy (1963) to be a junior synonym of Ascelis , but the concept of Gullan and Cockburn (1986) is that they are distinct, but closely-related genera. Cystococcus was revised by Semple et al. (2015). The genus contains 3 species, all of which induce galls (known as ‘bloodwood apples’ or ‘bush coconuts’) on the stems of Corymbia species ( Myrtaceae ). Cystococcus species may be the only insects to provide intersexual phoresy for their crawlers (see Gullan & Cockburn 1986; Semple et al. 2015). Adult males of all 3 known species were described in Semple et al. (2015).

Generic diagnosis based on morphology of adult males of 3 species of Cystococcus . Body up to 9.5 mm long,

with abdominal segments III–VII extremely long and narrow, making up between 2/3 and 3/4 of total body length; abdominal segments IV–VII each with a pair of internal sclerotised rods. Body setae few, short and hs; pores absent. Head with well-sclerotised ocular sclerites without striations or reticulations; setae few; simple eyes probably protruding; ocelli placed away from postocular ridge; scape and pedicel short, with most flagellar segments fused so that segment III very long, about twice length of head, with numerous spinose and/or broad fleshy setae, several of latter sometimes branched (digitate); capitate setae restricted to antennal apex, each antenna with at least 5 capitate setae. Thorax: prescutum large with prescutal setae; scutal setae present; scutellum rectangular with scutellar setae; postmesospiracular setae few; prosternum without a distinct median ridge; legs well developed; tibia with several spinose spurs; tarsi 1 segmented but with suggestions of a second; tibia and tarsi with stout fs; tarsal and claw digitules capitate; claw with a denticle and with a spine-like structure on basal section. Abdomen: abdominal segment VIII very short, subequal in length to penial sheath; penial sheath short, narrowing to a blunt apex, with several short setae.Aedeagus parallel-sided and blunt; basal rod apparently absent.

Key to adult males of Cystococcus species (after Semple et al. 2015)

1. Pedicel with numerous broad fleshy setae; antennae without digitate fleshy setae; scutum with scutal setae in two submedial broad bands of about 20 setae each; tibiae and tarsi without short peg-like setae; with one claw digitule appearing to arise from basal denticle; posterior abdominal segments and penial sheath with abundant fleshy setae.......................................................................................... C. campanidorsalis Semple, Cook & Hodgson.

- Pedicel without fleshy setae; antennae with some digitate fleshy setae; scutum with scutal setae in two narrow bands submedially; tibiae and tarsi with short peg-like setae; both claw digitules arising as normal from side of claw; posterior abdominal segments (except sometimes segment VIII) and penial sheath with few fleshy setae.......................................... 2

2. Scutellum with about 5 pairs of setae; simple eyes quite large, each 80–85 μm wide; setae on antennal flagellar segments mainly 33–40 μm long; basisternum with about 50 setae................................... C. echiniformis Fuller ( Fig. 31 )

- Scutellum with only 1 pair of setae; simple eyes small, each 45–50 μm wide; setae on antennal flagellar segments short, mainly 14–18 μm long; basisternum with fewer than 35 setae..................................... C. pomiformis (Froggatt)

Comment. Of the Gondwanan-group of eriococcids from Australia, long abdomens are also found on Tanyscelis species and Callococcus species. However, those of Cystococcus are otherwise very different. For further details, see key for Gondwanan-group species above and Semple et al. (2015).

Figures

FIGURE 31. Cystococcus echiniformis Fuller. Macropterous male. (Eriococcidae, Gondwanan group). Where A=bifurcated fleshy setae on antenna, D=fleshy setae on leg and abdomen, E=hair-like seta on antennae, G=dermal markings, N=side view of simple eye, and iii–viii=abdominal segmentation,