Hercinothrips trilineatus (Priesner)

GOLDARACENA, ARTURO & VIERBERGEN, GIJSBERTUS (BERT), 2022, A key to species of Hercinothrips, with one new species, and a neotype designation for H. trilineatus (Priesner), Zootaxa 5169 (4), pp. 322-330 : 328-329

Hercinothrips trilineatus (Priesner)

Hercothrips trilineatus Priesner 1932: 108 .

This species was described from a single female taken in Tanzania (Amani) on Bermuda grass ( Cynodon dactylon ) J. Vosseler 13.5.1907. However, this specimen was destroyed during the Second World War (Martin Husemann personal communication). Slides of three females labeled by Richard zur Strassen as H. trilineatus were found in the collection of Thysanoptera at Senckenberg Museum (Franckfurt). After careful comparison of these specimens with the original description of H. trilineatus , one of the females is here designated NEOTYPE bearing the following data: South Africa, Transvaal, on flowers of Convolvulus arvensis ) 18.x.1994 (C.J.Celliers), in Senckenberg Museum, Frankfurt ( SMF).

Redescription (based on the original description by Hermann Priesner):

Head and prothorax yellow, with three broad dark longitudinal joint lines, one in the middle, starting approximately at the level of the middle of the eye, two at sides that are wide on the prothorax and narrow at cheeks.

Thorax and abdomen dark reddish-brown, the last segments of the abdomen somewhat lighter; forelegs light yellow, barely or indistinctly shaded, mid-legs with dark thighs and light yellow tibias and tarsi, tibias have a broad, brown ring behind the base. Hind-tibia dark, at base with a narrow yellow ring.

Body bristles light. Antennal segment 1 coloured as head, hardly darkened, segment 2 about the colour of the central stripe of the head, 3 pure light yellow, 4 light yellow with a heavily darkened club, 5 at apex (of margin) somewhat less cloudy than 4, 6 to 8 dark brown. The wings are strong, almost uniformly darkened brown, fore wings in front of the vein fork with a blotchy lightening, which, however, is not hyaline, fore wings also a little light at the outermost base of the front edge, hind wings somewhat lighter gray, with black-brown longitudinal vein and almost hyaline, oval spot, just before the beginning of the longitudinal vein.

Head 120 (from the eyes dorsally 113) micrometers long, at the eyes 176 micrometers wide, these roughly faceted, 62-64 micrometers long, hardly or not with pubescence, slightly protruding in front as the antennae pits are deep. Interantennal process about 34 micrometers wide, truncated, almost straight in front. Vertex reticulated above, curved interocellar bristles at sides of fore ocellus; somewhat shorter post-ocellar bristles, belonging to the postocular row, 28 micrometers long, slightly behind the level of the posterior eye margin, located between this and the posterior ocelli. Head somewhat narrower at the cheeks than at the eyes, 173 micrometers wide. Vertex with a not very marked demarcation line between the front and back fields, which lies behind the postocellar bristles and against posterior margin of head, at least laterally, outside the brown central longitudinal line, consisting of transversely projected reticulated sculpture.

Antennal segments length (width): 20 (25), 42? (31), 70(19), 52-53(20), 45(20), 39(17), 15(8), 36(6) micrometers. The 1st segment small, somewhat rounded at sides, the 2nd with clear reticulated sculpture, which is indistinct on the 3rd and 4th segment, the 3rd with the ring thickening characteristic of Heliothripines, distal from the stalk, apically narrowed, also the 4th clearly vase-shaped, but much shorter than the 3rd, the 5th not vase-like, but narrowed in the last third towards the apex, the 6th truncated diagonally at the end; sense cones forked on the 3rd and 4th, but just moderately long.

Mouth cone normal, without particularity. Pronotum just about 113 micrometers long, 220 wide, straight on the sides, but rounded at the corners, anterior corners are barely noticeable, almost flattened like a lamella, pronotum surface with unclear reticulation. Fore legs, like the others simple, with a reticulate sculpture. Mesothorax wider than long, 310 micrometers wide.

Bristles on wings are very strong and dark, only near the base, in initial parts of the main vein and on the scale light and weak. Costa with 4 weak light and 19-20 (these are thinner towards the wing tip) dark, main vein with 4 light, basal, but behind the light field with 13 dark, strong bristles; second vein with 11 dark, strong bristles, scale with 4 weak yellowish dorsal bristles approached to the front edge.

The front and rear edges of the wings are fringed, the veins very strong, the beginning of the hind veins very thick.

Abdomen of this shriveled specimen short oval, strongly acuminate; the 9th segment above behind the base with a lateral comb plate, its marginal bristles B 2 about 85, B 3 70 micrometers long, yellow. Bristles weaker on the 10th segment, 70 and 56 micrometers long. The 10 segment is completely split. Body length (shriveled): 1.12 mm.

Measurements of the neotype (in microns). Body length 1498. Head, length 109; width across eyes 158; width across cheeks 163; width at basal collar 140; interval between eyes 95. Pronotum, length 100; width 195. Metascutellum, length 81; width 100. Fore wing, length 690; median width 38. Antennal segments II–VIII length (width): 37 (25), 59 (16), 47 (17), 39 (18), 29 (14), 13 (7), 37 (3).