Microdon devius (Linnaeus, 1761)

Scarparo, Giulia, Wolton, Robert, Molfini, Marco, Pinna, Luigi Cao & Ulio, Andrea Di Gi-, 2020, Comparative morphology of myrmecophilous immature stages of European Microdon species (Diptera: Syrphidae): updated identification key and new diagnostic characters, Zootaxa 4789 (2), pp. 348-370 : 360-362

Immature stages of Microdon devius

Third instar larva

Figs 7–9

Body width = 7.2 ± 0.6 mm; body length = 9.4 ± 0.9 mm (n = 10). Dorsal reticulation. Dorsal reticulation extended over the whole dorsal body surface. Each process resembling a sea anemone, being divided into a smooth, columnar trunk topped by a brush composed by 20–30 long, flexible filaments ( Fig. 7F ). Posterior spiracular tubercle. Longer than wide, subquadrate in dorsal view, concave medially, bulged sub–basally; distance between spiracular holes 1.8 times as long as their diameter ( Figs 8E, F ). The base of posterior spiracular tubercle encircled by a smooth cuticular crown ( Figs 8E, F ). Spiracular plates flattened to slightly concave, of variable shape, separated by a broad and deep midsagittal cleft. Marginal band. Processes on the marginal band apparently without basal articulated joints ( Figs 9E, F ). Processes on the marginal band of three types: type one long and single, apically fringed; type two short and bifurcate, apically 2–lobed; type three composed by two type one flanking a cluster of three spiniform setae ( Figs 9E, F ).

Puparium

Figs 10 , 11

Body width = 7.3 ± 0.4 mm; body length = 9.7 ± 0.5 mm (n = 10). Anterior spiracular tubercles. Length of each tubercle 2.25 times as long as wide and strongly curved ( Fig. 11F ), subcylindrical, slender, somewhat pointed at the apex, entirely furrowed by about 180 respiratory fissures ( Figs 10E, F ). Each fissure laying on a small papilla ( Fig. 10F ).

Figures

FIGURE 7. Dorsal reticulation of third instar larvae of M. myrmicae (A, B), M. analis (C, D) and M. devius (E, F); left, general view; right, detail of single reticulation processes. A = 400 µm; B = 50 µm; C, E = 500 µm; D = 100 µm; F = 200 µm.

FIGURE 8. Posterior spiracular tubercle of third instar larvae of M. myrmicae (A, B), M. analis(C, D), M. devius (E, F) and M. mutabilis (G, H); left, anterior view; right, apical view. A–H = 500 µm. ReFis, respiratory fissures; RH, respiratory hole; SC, smooth crown.

FIGURE 9. Marginal band of third instar larvae of M. myrmicae (A, B), M. analis (C, D) and M. devius (E, F); left, dorsal view; right, detail of marginal band. A = 500 µm; B, E = 300 µm; C = 100 µm; D = 50 µm; F = 200 µm.

FIGURE 10. Anterior spiracular tubercles of puparia of M. myrmicae (A, B), M. analis(C, D), M. devius (E, F) and M. mutabilis (G, H); left, lateral view; right, detail of respiratory fissures. A, E, G = 500 µm; B, F, H = 100 µm; C = 400 µm; D = 50 µm. ReFis, respiratory fissures.

FIGURE 11. Eggs of M. myrmicae trapping small drops of water (pointed with red arrows) with their volcano-like processes (A); third instar M. myrmicae larvae with larvae and workers of Myrmica scabrinodis (B); third instar larva and first instar larva (red arrow) of M. myrmicae with M. scabrinodis larvae, ventral view (C); M. myrmicae adult emerging from puparium, anterior view (D); two M. analis pupae and a puparium (E); M. devius pupa (F).