Suillia gigantea

Rosa-Gruszecka, Aleksandra, Woźnica, Andrzej Józef, Tereba, Anna, Szabłowski, Przemysław & Hilszczańska, Dorota, 2023, First molecular identification of Suillia gigantea (Meigen, 1830) (Diptera: Heleomyzidae), Zootaxa 5228 (2), pp. 122-136 : 126-127

Diagnosis for Suillia gigantea

Head: First flagellomere with extremely long plumose arista. Occipital (cerebral) setulae pale yellow. One strong vibrissa, often in addition with one or two small but distinctly visible additional setulae below it. Face protruding strongly forward. Eyes slightly ovoid. Gena wide, arched anteriorly, with 5–6 irregular rows of buccal setulae and about ½ of eye height ( Fig. 3 ).

Thorax: Mesonotum yellowish-orange, sometimes slightly dusted, without dark brown median stripe between dorsocentral bristles. All dorsocentrals emerge from distinct dark brown spots. In male the mesonotal disc more protuberant than in female. Pleura uniformly colored, with one katepisternal bristle and with few golden setulae before it. Meron fully bare. Scutellum dorsally setulose, with a bare narrow median stripe, significantly widening at base and apical part ( Fig. 4 ).

Legs: There is a marked sexual dimorphism, which is related to the structure and chaetotaxy of the male’s legs, because the female’s ones are similar to those of S. affinis Accordingly , the following features of chaetotaxy of legs are relevant only for male specimens: anterior tarsomeres with small ventral and slightly curved reddish thorn-like bristle, all femora are strongly thickened (look swollen) and covered anterodorsally by strong black bristles; all femora, all tibiae and first tarsomeres are posteroventrally distinctly long setulose and covered by yellow setulae with golden or rusty yellow sheen. Their length is greater than their width in all tibiae and first tarsomeres. All tarsi are slightly shortened, with two rows of spiny black setulae on the inner side of fore tarsomeres, and with flattened brownish-black tarsomeres III–V. The second tarsomere of the fore and hind legs of males is long setulose. All tarsomeres III–V with two inner rows of small bunches of black spines. Mid leg is a bit S-shaped and anteroventral basal part with some rows of thick, spiky black bristles. Hind knee with the adjacent top of femur is distinctly darker, almost brownish-black in color.

Wings: The wings resemble those of S. affinis , with slightly shorter costal spines and less numerous than in S. affinis .

Abdomen: The segments are fairly evenly colored, without the dark stripes on the segment margins typical of S. affinis . In the male, the abdominal sternites IV–V are densely covered with thin, golden-yellow setulae that protrude distinctly outward. The gonostylus is distinctly curved posteriorly and spoon-shaped, covered dorsally with very long yellow setulae ( Fig. 5 ). In the female: Abdominal segment VII in lateral view (without ovipositor extended) is distinctly shorter than segment VI (in S. affinis VII the abdominal segment is the same length or slightly longer than VI); the seventh sternite is trapezoidal-like in shape, with the anterior margin equal to the lateral margins and covered with pale yellow setulae only on the posterior one-third (the anterior and posterior margins are shorter than the lateral ones and, when flattened, they are more rectangular-like in S. affinis and covered with clearly visible brown setulae only, ca. in the posterior one-half). Four sperm receptacles, arranged in pairs are present. All well sclerotized, elongate and swollen, visibly narrowed at the base, and laterally curved at the apex, with a bloated spherical process at the end ( Fig. 6 ).

Figures

FIGURE 3. Suillia gigantea (Meigen, 1830). Head in lateral view (scale bar = 0,5 mm).

FIGURE 4. Scutellum of Suillia gigantea (Meigen, 1830)– dorsal view (scale bar = 0,5 mm).

FIGURE 5. Suillia gigantea (Meigen, 1830). Left gonostylus—Lateral-dorsal view (scale bar = 0,05 mm).

FIGURE 6. Suillia gigantea (Meigen, 1830). Spermathecae (scale bar = 0,05 mm).