Keys to third-instar larvae and puparia of Palearctic species of Colobaea

The only keys to genera of larvae and puparia of Palearctic Sciomyzidae are those of Rozkošný (2002) and Knutson & Vala (2011). Rozkošný (2002) provided a key to the puparia of two species of Colobaea ( C. distincta and C. pectoralis).

Key to larvae

1 Posterior end with two pairs of reduced, welt-like lobes (Fig. 16); dorsal surface of segments XI–XII tanned, with many fine scales (Fig. 22); anterior spiracles with 14–20 large, fingerlike papillae (Fig. 35). In species of Lymnaeidae . Ireland to Kazakhstan, northeastern Siberia, Russian South Maritime Territory......................................... C. bifasciella

– Posterior end with four pairs of conical lobes (Figs 15, 17–19); dorsal surface of segments XI–XII smooth, white; anterior spiracles with 12–16 small papillae. Various snail prey........................................................ 2

2 Anterior spiracles with 12–14 marginal papillae (Fig. 33); posterior spiracular plates with margins projecting at ends of slits (Fig. 30). In Gyraulus intermixtus . Iran, Pakistan ................................................... C. deemingi

– Anterior spiracles with 14–16 marginal papillae (Fig. 34); posterior spiracular plates subcircular. In species of Anisus, Bathyomphalus, Planorbis, and Lymnaeidae . Widespread in Europe and Middle East....................................... 3

3 Dorsal cornu of pharyngeal sclerite longer than ventral cornu, posterior margin of dorsal cornu irregular, slender; dorsal and ventral cornua converging posteriorly (Fig. 40). In Radix peregra and species of Planorbis . Trans-Palearctic east to eastern Siberia, south to Egypt, Israel .................................................................... C. punctata

– Dorsal and ventral cornua subequal in length, posterior margins less irregular, dorsal and ventral cornua not converging posteriorly (Fig. 41). In Anisus vortex and Bathyomphalus contortus . Trans-Palearctic east to Moscow and northern Kazakhstan; absent from southeastern Europe................................................................ C. pectoralis

Key to puparia

1 Robust form; anterior half expanded to close opening of snail shell whorl, posterior half smaller, twisted; anterior spiracles large, protrudent, with 14–20 large papillae (Figs 24, 27). In species of Lymnaeidae . Ireland to Kazakhstan, northeastern Siberia, Russian South Maritime Territory........................................................... C. bifasciella

– More slender; anterior end expanded to fit tightly within snail shell whorl, body form crescent shaped or subcylindrical in lateral aspect, not twisted; anterior spiracles protrudent or sessile, with 12–16 small papillae. In various species of snails..... 2

2 Anterior spiracles small, sessile; posterior spiracles large, protrudent; dorsal cephalic cap widened to close shell whorl, then narrowed abruptly (Figs 45–46). In Gyraulus intermixtus; septum material may be present. Southwestern Iran, Pakistan ............................................................................................... C. deemingi

– Anterior spiracles large, protrudent; posterior spiracles small, not protrudent; anterior end widened to close shell whorl but not abruptly narrowed (Figs 23, 26, 47–48). In species of Anisus, Bathyomphalus, Planorbis, and Lymnaeidae . No septum material present.............................................................................................. 3

3 Form slender, dorsoventrally compressed, crescent shaped in lateral aspect; anterior spiracles slender, strongly projecting anteriorly (Figs 23, 26). In Anisus vortex and Bathyomphalus contortus . Ireland east to Moscow and northern Kazakhstan ..... ............................................................................................ C. pectoralis

– Form robust, subcylindrical, not dorsoventrally compressed; anterior spiracles subcircular, projecting dorsally (Figs 47–48). In Radix peregra and species of Planorbis . Trans-Palearctic to eastern Siberia, south to Egypt, Israel ............. C. punctata