Pupa
Simulium rubithorax pupa.
Cocoon length dorsally 3.4-5.2 mm (mean = 4.3 mm, s.d. = 0.6, n = 25); ventrally 4.1-6.1 mm (mean = 4.9 mm, s.d. = 0.5, n = 25); pupa length 3.1-4.9 mm (mean = 4.0 mm, s.d. = 0.4, n = 25); gill length 2.5-5.4 mm (mean = 3.2 mm, s.d. = 0.6, n = 25).
Cocoon
Shoe-shaped, mid to pale brown with obvious collar and long, slender festoons joined to form loose lattice Cocoon surface smooth and translucent, with no individual fibres visible. In many localities balls of white amorphous material of unknown origin occur, sometimes attached to pupa and gills.
Gill
Light brown, protruding slightly beyond festoons, with eight forwardly-directed filaments Main trunk dividing basally into two primary branches each with four filaments. All filaments arise in basal quarter of gill, are slender with only faintly crenate margins and rounded distally, their surfaces densely covered with fine spicules.
Head (Frontoclypeus)
With 1+1 small, simple, frontal trichomes and 1+1 poorly developed, simple facial trichomes; frons with thickened margin at junction with clypeus. Frontal area with groups of platelets, but devoid of tubercles; facial area with regular rows of pointed and rounded tubercles.
Thorax
Well sclerotised with faint ring of small platelets loosely arranged around gill base (predominantly on dorsal side). Antero-dorsal surface with 5+5 (or 6+6) weakly developed, simple trichomes, three of which usually lie in line midway between gill base and dorsal margin. Central antero-dorsal region with trichomes but no tubercles, which are present only in patches on lateral and ventral areas and along mid line.
Abdomen
Tergite I completely sclerotised with numerous spine combs occupying most of posterior third to half of tergite; tergite II sclerotised in anterior half, often with small plates, 1+1 rows of 2-3 coarse hairs centrally, 1+1 hairs at outer end of row (often absent), anterior third with spine combs interspersed with hairs; tergite III with 4+4 simple hooks centrally, 1+1 simple hairs antero-lateral to them (frequently absent) and 1+1 anterior patches of spine combs; tergites IV, V with 1+1 rows of 1-4 hooks usually present and 1+1 anterior patches of spine combs; tergites VI-VIII with 1+1 anterior patches of spine combs (extending to lateral margins in tergites VII, VIII); tergite IX with rounded, apical tubercles not spines. Abdominal sternites III, IV with anterior band of spine combs; sternite V with 2+2 close, simple hooks and anterior band of spine combs, most prominent above hooks; sternites VI, VII with four evenly-spaced, simple hooks and anterior band of spine combs; sternites VIII, IX with central band of spine combs, often weakly defined in sternite IX.