Paragus pusillus, Stuckenberg, 1954

Stuckenberg, B. R., 1954, The Paragus Serratus Complex, With Descriptions Of New Species (Diptera: Syrphidae), Trans. R. Ent. Soc. Lond 105 (17), pp. 393-422 : 401-404

Paragus pusillus sp. n.

A narrow, dark species with very short mesonotal pile. The vertex of the male is closed behind by two posteriorly converging strips of tomentum. The femora are testaceous and lack bands of darker colour. The abdomen is very dark, except for a patch of lighter colour over the second and third segments. The females have a small, oval, diagonal spot of pollen on each side of the anterior ocellus. The styles are foliaceous and there is a prominent, median, finger-like process on the ventral surface of the penis-sheath. The ejaculatory apodeme is smaller than the hypopygium.

Mak.-Hrlead: Face creamy-yellow, with indistinct punctures and a sparse short silvery white pile; facial stripe extends upwards to base of antennae, and is almost colourless except over the facial tubercle, where it is pale brown. Oral tubercle piceous and surrounded by a strip of light brown. Antennae shorter than the face; h t segment badious; second similar, but dark above; third segment crineous, becoming brownish below, and twice as long as first two together. Vertex black with an admixture of brown, showing pale blue and cupreous reflections; bordered posteriorly by two small arms of silvery tomentum which converge at edge of occiput and extend anteriorly, ending at sides of vertex just past upper corners ofcompound eyes. Stripes of hair oneyes indistinct, the outer on each eye being almost absent and the inner two intermingling. Thorax: Mesonotum shining black with metallic blue and grey, and some slight cupreous reflections; conspicuouslypunctate. Mesonotal pile very short and scanty-it is bombycinous. Stripes on mesonotum moderately heavy, more so than in P. mpricorni; converging anteriorly for a short distance, and not ending in sharp points posteriorly. Pileonposterior humeri slightly longer and paler. Scutellum creamy on apical third, colourless on middle third, end basally black with a strong admixture of brown. Fourteen long, yellow scutellar teeth. Legs: Femora testaceous basally, creamy-yellowon apical fifth. Posterior tibiae rreamy-yellow basally, distally ferrugino-testaceous like the posterior tarsi. The two anterior pairs of tibiae creamy-yellow on basal half, testaceous distally. The two anterior pairs of tarsi testaceous, paler than femora. Wings: Hyaline, with a yellow stigma that is slightly tinged with brown. Apex of subcosta pale, almost the eame colour as stigma. Remainder of veins ligneous brown, not as heavy as in cuprimmi. Abdomen (fig. 9): Very different from that of P. capricorni . Very dark, especially on fist and last two segments. First segment almost entirely fusco-piceous except for a small, median, testaceous patch on its posterior margin. Second segment reddish in the centre, pale amber laterally, then slightly reddish.brown, the margins and shoulders fusco-piceouswith pale blue reflections. Third segment dark reddish-brown with a darker median area, and beooming very dark on sides. Fourth segment entirely fusco-piceous, the fifth similar, except that it is margined with reddish-brown. Anterior vittae distinct, though not clearly dehed against the pale colour of the second segment; middle and posterior paira distinct, and each pair almost meets in the midline. Third and fourth segments distinctly &ate; their sides more rounded than in P. cupicorni. Abdomen not robust, and narrow, with hardly prominent shoulders and margins nearly parallel; its apex rounded. Transverse troughs in which the vittae of third and fourth segments lie large and deep, especially the anterior pair. Tergites distinctly sculptured, inoluding fist segment; in addition there are numerous deep, round punctures evenly distributed over all tergites. A thin covering of short, very inconspicuous,reclinate black hairs, and longer, sparse, thin, white hairs present, erect on first segment and reclinate elsewhere. Genitalia ( fig. 7 ): Epandrium rectangular, with posterior margin inclined at an angle to lower margin. Ratio of upper to lower margins 5: 8. Epandrium about aa deep as length of upper margin; its lower, posterior corner broadly rounded and produced. Cerci long, flattened and moderately prominent. Styles foliaceous when seen from the side, with upper and lower margins sinuate, upper more so than lower, both coming together at an acute angle and ending in a somewh.tt deflexed point. Inferior claspers well developed; extending ventrally into rounded lobes that project below level of penis sheath and bend cephalad a little; dorsally they are tnincated at about level of lower margin of epandrium, with dorsal edge concave and meeting outer margin in a point; each about aa long as epandrium is deep, Superior claspers borne on broad lobes with straightened edges.

Ventrally penis-sheath bears a finger-like projection that has a slightly concave inner surface, and which is about half a8 long as an inferior clasper. Ejaculatory apodeme missing in the preparation.

Length 6.2 mm.

Holotype male, SOUTHERN RHODESIA: Sawmills , 23.x. 1922. In the National Museum of Southern Rhodesia, Bulawayo.

Female.-Facial stripe as broad as facial tubercle, and light ligneous brown. Tomentose strips on h nt linear and uniformly wide, and each with a short, beak-like, incurved hook of tomenturn at upper end. Also a small, oval, diagonal spot of pollen on eaoh side of anterior ocellus. Front black, with some metallic reflections. Stripes of hair on eyss distinct. Apical half of scutellum creamy-yellow; fourteen ecutellar teeth. Abdomen like that of holotype, but darker; entirely piceous behind first pair of vittae and has a wq dark fusiform patch in centre of second tergite. Abdomen (fig. 10) rounded in crosshection and slightly carinate, its shape similar to that of abdomen of holotype, but margins very gently curved from shoulders to apex. Fourth and fifth sternites shining black.

Length 64 mm.

Allotype female, SOUTH-WEST AFRICA: Zesfontein, ii. 1925. In the South African Museum, Cape Town.

Paratypes: SOUTH-WEST AFRICA: Kaross , 1 ♂, 1 ♀; Zesfontein, 1 ♂, 2 ♀; Warmbad, 5 ♀, ii. 1925. In the South African Museum, Cape Town.

The males are like the holotype, except that they are smaller and darker, the thorax of each specimen with only slightly coloured reflections. Each has only ten scutellar teeth and the yellow of the scutellum occupies the apical Mf. Their genitalia differ in having the styles with only slightly sinuate margins. The ejaculatory apodeme ( fig. 8 ) from one paratype is very different from that of P. capricorni . It is much smaller than the hypopygium, and consists of a stem-like portion which bears a hood. The stem is very broadly flattened at its junction with the hood, expanding laterally into short, flattened flanges, and then tapering off quite slowly for a distance about equal to the greatest width of the hood-at this point it constricts slightly and then becomes cylindrical for a short length, finally dilating into a funnel-shaped apex. The hood is ellipsoidal, slightly distorted, and concave; dorsally it is furrowed over its greatest width along the line of attachment of the stem.

Of the female paratypes, two (Warmbad) are of the same size as the allo. type, the rest smaller. They all have the coloured reflections of the thorax very poorly developed. The number of scutellar teeth varies from nine to fourteen. All appear to be almost completely black except for the lighter colouring on the second abdominal segment, and some have very reddish legs. Shortest paratype 4.6 mm., longest paratype 6.8 mm.

Remurks.-This species is distinguished by its small size, generally dark coloration and narrow body. It is easily separated from P. capricorni by the characters given in the key above, and from the other African species by its very short mesonotal pile. It appears to be most closely related to P. serratgs (Fabricius). The dark coloration of the specimens from South-West Africa my be due to development under the semi-arid conditions usually prevailing there.

Figures

FIGS.7-8.-Parappusillus sp.n. (7) Hypopygiumofholotype. (8) Ejaculatory apodeme.