Eumerus superbus Shannon 1927

Adomako, Abigail Kusiwaa, Gasu, Edward Ntim, Mensah, Jehoshaphat Oppong & Borquaye, Lawrence Sheringham, 2020, What do Eumerus Meigen larvae feed on? New immature stages of three species (Diptera: Syrphidae) breeding in different plants, Organisms Diversity & Evolution (New York, N. Y.) 20 (2), pp. 267-284 : 273-275

Eumerus superbus Shannon 1927

( Fig. 1b ; 3c ; 4c ; 5c, d ; 6e, f ).

Shape and size of puparium ( Fig. 1b ) Subcylindrical in cross-section, posteriorly tapered, pale brown. Surface of the tegument entirely reticulated, as if it had reptilian scales. Mesothoracic prolegs absent. Abdomen with 6 pairs of diffuse locomotory organs, bearing diffuse rows of minimum crochets posteriorly curved, very similar to the surrounding spicules. Anal segment with three pairs of lappets, middle ones divided in two projections, 3rd pair very robust and longer than the rest. All lappets bearing 2–6 sensilla, 3rd one having additional small lateroposterior sensilla. Length: mean 9.58 mm (range 7.71–10.66); width: mean 4.87 mm (range 3.98–5.22); height: mean 4.1 mm (range 3.38–4.38) (n = 4).

Head skeleton ( Fig. 3c ) Mandibular hooks highly sclerotized and mandibular lobes fleshy, well-developed, fused with the mandibles; dorsal cornu shorter and wider than ventral cornu, dorsal cornu tapering, fin shaped; final part of the ventral cornu with a dorsal projection facing upwards consisting of a sclerotized fold facing the lumen of the cavity; labrum prominent, sclerotized; pharyngeal sclerite long, 1/3 the length of the dorsal cornu; tentorial arm more sclerotized to the frontal and posterior ends than in the middle, reaching at mid ventral cornu, finished by two sclerotized teeth dorsally facing; tentorial bar heavily sclerotized; mandibular hooks 0.32 mm long, without accessory teeth, apical part of the hooks almost triangular in lateral view and, in apical view, 14% more separated at the apex than the basal width.

Anterior spiracles ( Fig. 4c ) Spatula shaped structures, light brown and shiny, dorsoventrally flattened, narrow at the base, wider to the apex, ≈ 198 μm long × 184 μm wide at the base, 16% wider to the apex at their maxima, almost equally longer than broad. Nine linear spiracular openings on a single row along the arched apex. Smooth surface with some wrinkles towards the base.

Pupal spiracles ( Fig. 5c, d ) Cylindrical structures, tapering to the tip, ≈ 574 μm long × 188 μm wide, 3× longer than broad at the base. Smooth surface, lightly granulated and reticulated along the structure, apex more granulated and reticulated that the rest of the PS. Irregularly spaced round spiracular tubercles along the distal half of the dorsal surface, absent on the ventral surface, bearing 3–6 linear spiracular openings radially arranged.

PRP ( Fig. 6e, f ) Dorsoventrally flattened tube in cross-section; α = 366.2 μm; β = 704.23; α/β = 0.52. Below transverse ridge, surface with fine transversal striations with longitudinal and diagonal wrinkles; above ridge smooth, with a constriction forming a subtle transversal groove, half distance from the transverse ridge to the spiracular plate, lightly punctured; 3 pairs of sinuous spiracular openings, curved to themselves, with 4 pairs of divided and simply branched setae, not feathery, around the margin of the spiracular plate. Spiracular plate with an evident dorsoventral constriction at the center.

Species distribution Only known to Australia ( Evenhuis and Pape 2019).

Material examined 4 puparia. 2 males and 1 female bred from Lepidozamia peroffskyana seed cones, Leg. C. Burgess, 1970; 1 female bred from Macrozamia communis , Leg. M. S. Upton, 1965. All known specimens of this species are reared and no adult has yet been caught in the wild (Hauser, pers. comm.) Deposited at ANIC .

Figures

Fig. 1 General shape of Eumerus puparia, dorsal view. a Eumerus alpinus. b Eumerus superbus. Scale lines: a and b = 2 mm

Fig. 3 Head skeletons of Eumerus, lateral view. a Eumerus alpinus. b Eumerus figurans. c Eumerus superbus. D dorsal cornu, L mandibular lobe, M mandibular hook, P pharyngeal ridges, T accessory tooth, V ventral cornu. Scale lines = 250 μm

Fig. 4 Anterior spiracles (AS) of Eumerus larvae and puparia, apicoventral view. a Eumerus alpinus, puparium; SEM. b Eumerus figurans, larva; stereo microscope. c Eumerus superbus, puparium; SEM. O spiracular opening. Scale lines: a = 50 μm; b = 200 μm; c = 100 μm

Fig. 5 Pupal spiracles (PS) of Eumerus puparia (left) and details of the tubercles bearing spiracular openings (right). a, b Eumerus alpinus. c, d Eumerus superbus. O spiracular opening. Scale lines: a = 100 μm; b and d = 50 μm; c = 250 μm

Fig. 6 Posterior respiratory processes (PRP) of Eumerus lar- vae and puparia in dorsal view (left) and polar view (right). a, b Eumerus alpinus, puparium; SEM. c, d Eumerus figurans, lar- va; stereo microscope. e, f Eumerus superbus, puparium; SEM. α distance from the trans- verse ridge to the center of the spiracular plate, β width of the PRP at the transverse ridge level, C* spiracular scar, O spiracular opening, R transverse ridge, S spiracular seta. Scale lines: a and e = 500 μm; b and c = 250 μm; d = 100 μm; f = 200 μm