Lithax musaca Malicky 1972

Waringer, Johann, Graf, Wolfram, Sipahiler, Füsun & Malicky, Hans, 2017, The larvae of Silo chrisiammos Malicky 1984 and Lithax musaca Malicky 1972 (Trichoptera: Goeridae), including a key to the Goeridae larvae of the Eastern and Hellenic western Balkan regions, Zootaxa 4306 (1), pp. 67-80 : 72-73

Description of the final instar larva of Lithax musaca Malicky 1972

Biometry. Body length = 8.9 mm, head width = 1.03 mm (n= 1). All morphological characters identical to those of S. chrisiammos except as noted below.

Head. Head surface very coarsely granulated, especially between eyes (= ‘honeycomb pattern’; Figs. 18–19). In lateral view, head profile angular (Fig. 19). Frontoclypeus at height of central constriction sharply bent backwards; posterior frontoclypeal section with shallow horseshoe-shaped depression, its rim strongly marked with honeycomb pattern (Fig. 19).

Ventral apotome yellowish brown, broadly triangular; anterolateral lobes (as in L. obscurus and S. chrisiammos ; Fig. 4 ) lacking. Postgenal suture approximately 48% of apotome length ( Fig. 20 ).

Thorax. Pronotum surface yellowish, dark along anterior border and at posterolateral sections; very coarsely granulated in honeycomb pattern ( Fig. 21 ). Central pronotal section with ridge-like longitudinal hump gradually descending posteriorly to pronotal surface ( Fig. 21 n), thereby reaching posterior pronotal border ( Fig. 22 , arrow). Ridge creating pair of dark brown lateral dents ( Fig. 21 d) with coarse honeycomb pattern ( Fig. 23 ). Without obvious muscle attachment spots.

Mesonotal sclerites yellow, with triangular brown coloration on sclerite 3 tapering posteriorly; these dark patches very coarsely granulated in honeycomb pattern ( Fig. 24 ). Mesepisternal distal section tapering to blunt apex ( Fig. 25 ). With additional setae on proximal half of posterior faces of 1 st femora .

Abdomen. Dorsal gills present at most from 2nd segment (postsegmental position) to 7th segment (postsegmental position). Ventral gills ranging from 2nd (postsegmental) to 7th segment (postsegmental). Anal claw without accessory hook.

Case. Prepupal case flattened, 8.9 mm long, width at anterior opening 6.5 mm, at posterior opening 5.0 mm, height 3.5 mm (n = 1). Ballast stones large, up to 5x 3 mm ( Fig. 26 ). Posterior case membrane covered by one large mineral particle (2.7x2.0 mm), as frequently observed in Lithax cases.

Figures

FIGURES 1 – 6, Silo chrisiammos Malicky 1984, final instar larva: 1, larva, frontal (black arrow: antenna); 2, head, frontal (d: parietal dent); 3, head, right lateral; 4, head, ventral; 5, pronotum, dorsal (d = pronotal dent; n = nose-shaped central bulge; s = partial transverse suture). 6, pronotum, right lateral (d = pronotal dent; n = nose-shaped central hump; arrow = posterior end of central hump descending to pronotal surface distinctly anterior of caudal pronotal border). Scale bars: 1 mm (Figs. 1, 2, 4, 5, 6) and 0.5 mm (Fig. 3).

FIGURES 20 – 24, Lithax musaca Malicky 1972, prepupa: 20, head, ventral; 21, pronotum, right dorsolateral (d = pronotal dent with honeycomb sculpturing; n = nose-shaped central hump); 22, pronotum, right posterolateral (arrow = posterior end of central hump descending to pronotal surface at caudal pronotal border); 23, left pronotal dent, detail of honeycomb pattern; 24, head, thorax and anterior abdomen, dorsal (numbers 1 – 4: arbitrarily assigned sclerite numbers on meso- and metanota). Scale bars: 1 mm (Figs. 21, 22, 24) and 0.5 mm (Figs. 20, 23).

FIGURES 25 – 26, Lithax musaca Malicky 1972, prepupa: 25, left mesepisternum, dorsal; 26, prepupal case, dorsal. FIGURES 27 – 28, Goera pilosa (Fabricius 1775), final instar larva; 27, thorax, dorsal (arrow = pronotal dorsal hump; numbers 1 – 3 = arbitrarily assigned sclerite numbers on meso- and metanota); 28, detail of dorsal pronotal hump, dorsal. FIGURE 29, Silo nigricornis (Pictet 1834), final instar larval pronotum, dorsal. FIGURE 30, Silo graellsii Pictet 1865, final instar larval pronotum, right dorsolateral (a = large central hump; b = smaller lateral humps). Scale bars: 1 mm (Figs. 26, 27, 29, 30) and 0. 5 mm (Figs. 25, 28).