Ramiheithrus virgatus Neboiss, 1974

St Clair, Rosalind M, 2021, The unusual genus Ramiheithrus (Trichoptera: Philorheithridae), Memoirs of Museum Victoria 80, pp. 159-168 : 160-164

Ramiheithrus virgatus Neboiss, 1974 :

Figures 1–21

Type Material. Holotype male, Victoria. McKay Creek, Sassafras Gap , 36° 36' S 147° 47' E, 2 February 1974, A. Neboiss ( NMV TRI-4558 ) . Paratypes 8 males, collected with holotype ( NMV TRI-4559 to 4566 ) .

Other Material examined. New South Wales. Alpine Creek Kiandra, 35° 52' S 148° 29' E, 20 January 1966, 3 males 2 females ( NMV TRI-29289 ), 16 January 1968, 1 male ( NMV TRI-29288 ), 13 December 1974, 2 males, 3 females ( NMV TRI-29290 ), E.F. Riek . Victoria. Roadside trickles 1.2 km N of Sassafras Gap, − 36.6° E 147.79° S, 10 February 2010, 1 larva ( LTUT720-12 ) ( NMV TRI-54703 ), D. Cartwright and R. St Clair, 19 December 2013, 1 larva ( NMV TRI-55169 ), D. Cartwright; Roadside seep 1.6 km N of Sassafras Gap, 10 February 2010, 1 larva ( NMV TRI-55167 ), 11 February 2010, preserved assorted dates to 21 February 2010, 3 reared males, 1 reared female, 2 male pupae, 1 female pupa all with larval case and sclerites, 6 larvae ( NMV TRI-54806 to 54815 ), D. Cartwright and R. St Clair; Whites Bridge Mt. Buller Road 5 km SE Mirimbah, 37° 08' S 146° 26'E, 22 Mar 1985, 1 male A. Neboiss ( NMV TRI-29291 ), 1 male, 2 Jan 2011, M. Shackleton ( LTUT723-12 ) ( NMV TRI-54702 ) .

Diagnosis. As for the generic diagnosis with the following additions. Male genitalia with segment X median lobe elongate, longer than lateral lobes (figs 2, 3).

Larva distinguishable from larvae of the two other species in the genus by the absence of small anterior sclerites on the prosternum, the more strongly developed brush of small spines apically on the hind legs (fig. 14) and the reddish-brown head and thorax (fig. 11). Collection of additional larval specimens of the two undescribed species may show these larval characters to not be as diagnostic.

Description. Revised after Neboiss (1974). As for the generic description with the following. Antennae rami dark brown, antennal segments yellowish. Forewings irregularly mottled greyish brown, a distinct pale oval spot close to wing margin within fork 3, smaller and less conspicuous ones between the veins above and below it (fig. 1); R1 joins R 2 in males and females although R1 joins the wing margin instead in most specimens collected near Kiandra (fig. 5) and a few from Sassafras Gap.

Male genitalia: segment X median lobe laterally compressed, lobe longer than lateral lobes; lateral lobes flat, somewhat truncate in lateral view; phallus comes to a point apically, curved downwards ventrally; inferior appendages somewhat truncate distally in ventral view, irregular or with a concavity (rarely 2) apically in some specimens (figs 2, 3).

Female. Antennal rami on segments 3 to 11, 12, or 13, rami less than half the length of those in males. Forewings with forks 1 to 5 present, forks 3 and 4 on long footstalks, hind wings similar to male (fig. 5). Sternite VIII with a band of short pale setae along posterior margin (figs 6, 7). Genitalia: tergite IX very broad and sclerotised dorsally, narrowly cleft mesally, medial notch on posterior margin. With a pair of depressions laterally on segment, with a weak carina along dorsal margin of each. Sternite IX with triangular sclerotised area on anterior half of segment, fleshy laterally and posteriorly (figs 6–9). Simple, apical lobes fused with segment X or lost.

Pupa. Head with a pair of prominent rounded, tuberculate warts on the frons taking up most of the width of the frons which are similar to, but more prominent than, those of Aphilorheithrus and Kosrheithrus ; a pair of long setae dorsally medially on the head between the antennae, a second pair just dorsal to the tuberculate warts (fig. 18), labrum with 3 pairs of setae in each dorsolateral corner; mandibles bladelike in apical half, narrowing to a point, straight and serrate on inner margin, rounded and smooth on outer margin, with a pair of medium length setae basally (fig. 19); each scape with medium length setae, 1 pair mesal dorsal and 1 pair distal ventral (fig. 18). Legs without swimming fringes, rarely a weak fringe on at least one mid leg. Abdomen with pairs of anterior dorsal hook plates on segments 3 and 4 each with 2 to 4 teeth, segments 5, 6 and 7 each with 3 to 6 teeth; pair of posterior hook plates on segment 5 each composed of a row of 16 to 25 spines, many bifid (usually different number on each side) covering most of the width of the segment and with a short gap between each plate, spines as long as plates (fig. 20). Last abdominal segment elongate subtriangular, with 2 pairs of long setae mesally, ventrally (fig. 21). Anal processes as for the family: lightly sclerotised, long, very narrow and slightly curved apically, each with a short dark pigment band close to the apex and without setae (figs. 20, 21). Larval case with anterior pupal closure a disc of silk without any openings holding on a capping stone.

Larva. As for diagnosis. Final instar larva head capsule width across eyes 1.3 to 1.4 mm.

Remarks. Note that the variation found in wing and genitalic structures of the male were found in all populations.

Figures

Figures 1–4. Ramiheithrus virgatus male: 1, Sassafras Gap body lateral; 2, Mt Buller genitalia ventral; 3, Kiandra genitalia lateral; 4, Mt Buller abdomen lateral showing elongate spiracles on segments. ia = inferior appendage, sa = superior appendage, IX = segment IX, X = segment X.

Figures 5–9. Ramiheithrus virgatus female: 5, Kiandra right fore and hind wings; 6, Kiandra genitalia lateral; 7, Sassafras Gap genitalia lateral; 8, Sassafras Gap genitalia dorsal; 9 Sassafras Gap genitalia ventral. d = depression.

Figures 10–17. Ramiheithrus virgatus Sassafras Gap larva: 10, head dorsal; 11, head, thorax and first abdominal segment dorsal; 12, head, thorax and first abdominal segment ventral; 13, foreleg anterior face lateral; 14, legs posterior face lateral; 15, abdominal segment IX dorsal; 16, last abdominal segment ventrolateral; 17, case and posterior closure. cs = cluster of setae, pc = particles closing posterior opening.

Figures 18–21. Ramiheithrus virgatus Sassafras Gap pupa: 18, shed cuticle head and thorax dorsal; 19, anterior of head ventral; 20, shed cuticle abdomen dorsal; 21, last abdominal segment ventral.