Eumerus alpinus Rondani 1857

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 : 270-272

Eumerus alpinus Rondani 1857

( Figs. 1a ; 3a ; 4a ; 5a, b ; 6a, b ).

Shape and size of puparium ( Fig. 1a ) Subcylindrical in cross-section, posteriorly tapered, dark brown. Surface of the tegument entirely coated with curved spicules. Mesothoracic prolegs absent. Abdomen with 6 pairs of locomotory organs bearing 1 row of crochets posteriorly curved. Anal segment with three pairs of lappets, middle ones divided in two projections, 3rd pair longer and more curved than the rest. All lappets bearing 2–3 sensilla. Length: 9.37 mm; width: 4.82 mm; height: 4.24 mm (n = 1).

Head skeleton ( Fig. 3a ) Mandibular hooks highly sclerotized and mandibular lobes coriaceous, well-developed, fused with the mandibles; dorsal cornu shorter and wider than ventral cornu, dorsal cornu tapering, fin shaped; labrum not prominent, highly sclerotized; pharyngeal sclerite very sclerotized, long, 1/3 the length of the dorsal cornu; tentorial arm sclerotized, wide, ending at mid ventral cornu; tentorial bar heavily sclerotized; mandibular hooks 0.42 mm long, with 2–3 accessory teeth and, in apical view, 21% more separated at the apex than the basal width.

Anterior spiracles ( Fig. 4a ) Cylindrical structures, dark brown and shiny, lightly curved to the tip, ≈ 101 μm long × 56 μm

wide, 1.8× longer than broad, with two linear spiracular openings at the apex. Smooth surface without any ornament.

Pupal spiracles ( Fig. 5a, b ) Subconic structures, short and thick, tapering to the tip, ≈ 306 μm long × 192 μm wide, 60% longer than broad at the base, separated from each other 5.8 times their length. Smooth surface along the structure except for the granular apex. Regularly spaced round spiracular tubercles along the dorsal surface, absent on the ventral surface, bearing 5–7 linear spiracular openings radially arranged.

PRP ( Fig. 6a, b ) Subcylindrical to ovoid tube in cross-section, tapering posteriorly; α = 387.32 μm; β = 570.42; α/β = 0.68. Below transverse ridge, surface with fine transversal striations with longitudinal wrinkles; immediately above ridge punctured, then granulated towards the apex until almost smooth; 3 pairs of sinuous spiracular openings, with 4 pairs of divided and simply branched setae, not feathery, around the margin of the spiracular plate. Spiracular plate with a light dorsoventral constriction at the center.

Species distribution Spain, southern France, Switzerland, Italy (excluding Sicily), parts of the former Yugoslavia, Bulgaria and Romania ( Speight 2017).

Material examined 1 puparium with emerged female, Madeloc, env. Banyuls-sur-mer, Pyrénées-Orientales, F r a n c e. L a r v a e x r o o t o f A s p h o d e l u s r a m o s u s ( Xanthorrhoeaceae ). Leg. M. C. D. Speight. 2013. Deposited at CEUA.

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