Simulium (Shewellomyia) Peterson, 1975

Figs 7, 27, 43, 63, 82–83, 112, 124–125

Hagenomyia Shewell, 1959: 83, figs 1–9 (as subgenus of Simulium) (preoc.). Type species: Simulium pictipes Hagen, 1880 . nom. praeoc.

Shewellomyia Peterson, 1975: 111 (as subgenus of Simulium). Type species: Simulium pictipes Hagen, 1880 . nom. nov.

Species

Simulium claricentrum Adler, 1990

S. innoxium Comstock & Comstock, 1895

S. pictipes Hagen, 1880

Diagnosis

Female

Scutum black to dark brown; scutal pattern present (Fig. 7). Cibarium unpigmented anteromedially and unarmed. Tarsal claw without subbasal tooth. Hypoginial valves subtriangular, shorter than sternite VIII width, forwardly directed. Anal lobe subrectangular with ventral extension shorter than the cercus base width (Fig. 27).

Male

Ventral plate (Fig. 43) two times longer than wide, deeply notched (reaching about half of the ventral plate body width); lateral shoulders projected; posteromedial process absent. Gonocoxite wider than long, with base double in width than gonostylus width at their point of intersection (Fig. 63). Gonostylus cylindrical, distinctly longer than gonocoxite, with blunt apex and without apical spinule (Fig. 63). Parameres with both distinctly large and small accessory spines.

Pupa

Cocoon aperture upward directed, separated from substratum, not corbicular (Figs 82–83). Gills shorter than pupa body, with trunk development, and totally enclosed by cocoon anterior margin; with nine filaments arranged in different planes (tridimensional); filaments flexible, cylindrical, with blunt apices concolorous with rest of gill; inferior branch multibranched. Thoracic trichomes simples.

Larva (last instar)

Cephalic apotome spots insertion area pigmented (Figs 124–125). Postocciput extended over the cervical sclerites. Antenna equal or shorter than labral fan stalk, without secondary annulations. Mandibles with pre-apical teeth shorter than apical tooth; two mandibular serrations of different sizes. Postgenal cleft triangular; postgenal bridge length equal or less than hypostomal length. Hypostomal anterior margin straight; hypostomal teeth extended beyond anterior margin of ventral wall of hypostoma; medial tooth at same level as lateral ones; lateral serrations well-developed, sharp; paralateral teeth absent. Body surface glabrous. Abdomen gradually expanding posteroventrally to last segments, then abruptly contracting to posterior proleg (Fig. 112). Anal sclerite no encircling base of posterior proleg. Posterior portion of abdomen without sclerotized accessory plates. Without 1+1 ventral tubercles. Rectal papillae with three multi-branched lobes.

Remarks

Simulium (Shewellomyia) was recovered as monophyletic and stable, based on three synapomorphies (Fig. 1, Table 2, node 7), therefore we propose its revalidation.

Distribution

Simulium (Shewellomyia) is distributed in the Nearctic Region, recorded from the central-eastern regions of Canada and the USA (Adler 2020).