Homalocnemis nigripennis Philippi, 1865

Rafael, José A., Marques, Dayse W. A., González, Christian R. & Sinclair, Bradley J., 2022, Review of Homalocnemidae of Chile with a key to species and descriptions of male and female terminalia (Diptera: Empidoidea), Zootaxa 5222 (2), pp. 168-178 : 171-172

Homalocnemis nigripennis Philippi, 1865

( Figs 1–12 , 28 )

Homalocnemis nigripennis Philippi, 1865: 752 . Type-locality: Chile.

Holotype. Male (not found in MNNC, presumably lost). Chile.

Distribution. Chile: Valparaiso, Santiago ( Fig. 28 ).

References. Reed, 1888: 301 (cat.); Bezzi, 1905: 457 (list); Kertész, 1909: 8 (cat.); Collin, 1928: 54 (com.); Melander, 1928: 14 (dist.); Collin, 1933: 29 (redes., fig. 6a); Stuardo, 1946: 104 (cat.); Smith, 1967: 9 (cat.); Chvála, 1991: 13 (com.); Camousseight, 2005: 90 (list); Yang et al., 2007: 280 (cat.).

Diagnosis. In addition to features in the key, this species is distinguished by the long, narrow digitiform epandrial process, male cerci separate from epandrium and female sternite 8 not greatly enlarged and apex weakly bilobed.

Redescription. Wing length: 5.0– 5.1 mm. Male ( Figs 1, 3 , 6–8 ). Predominantly gray pruinose, especially mesopleuron, postpronotal lobe and notopleuron; prescutellar depression with long, anteriorly pointed pruinescent stripe, extending to near apex of scutum; front of scutum gray pruinose, with brown vittae along dorsocentral rows, apex of scutum and postsutural region ( Figs 1, 4 ). Palpus with long whitish setae. Wing darkly infuscate, anal lobe well developed in both sexes ( Figs 1–5 ). Vein R 2+3 strongly upcurved distally around pterostigma, ending well proximal to level of branching of vein R 4+5. Section between veins R 2+3 and R 4 equal to or longer than section between veins R 4 and R 5. Hind tarsomere 1 slightly swollen ( Fig. 3 ). Tergite 8 less than half-length of respective sternite ( Fig. 7 ), narrowed medially ( Fig. 6 ); sternite 8 with desclerotized or depigmented medial area, with intersegmental membrane pigmented or weakly sclerotized posterolaterally ( Fig. 7 ); remaining pregenital sclerites unmodified. Terminalia not highly sclerotized. Epandrial lamellae subrectangular, fused narrowly along dorsal bridge; with narrow, digitiform subapical process; dorsal margin with long, dense setae, nearly as long as width of epandrium ( Fig. 6 ). Cercus oval, rounded posteriorly, with short dense ventroapical setae; not fused to epandrium or surstylus ( Figs 6, 7 ). Hypoproct membranous medially, clothed in setulae laterally. Subepandrial sclerite broadly V-shaped, extending as bacilliform sclerites to surstylus; surstylus arched dorsally with apical notch; basally fused with epandrium ( Figs 6, 8 ). Hypandrium ( Figs 7, 8 ) with gonocoxal apodeme short, narrow, not greatly expanded horizontally; gonocoxal apodemes united dorsally by upright phallic plate; phallic plate paired, narrowly extending dorsally to base of subepandrial sclerite, opposite dorsal bridge of epandrial lamellae. Postgonites not differentiated. Hypandrium mostly fused with phallus, with apex of phallus emerging apically ( Fig. 8 ); without lateral projections. Ejaculatory apodeme slender, elongate, positioned within hypandrium ( Fig. 8 ).

Female ( Figs 2, 4–5 ). Same pattern of color as male ( Fig. 1 ). Sternite 8 broadly joined ventrally, with apex weakly bilobed ( Figs 10, 11 ), not greatly enlarged, subequal to anterior portion of sternite 8; sparsely clothed in short setae. Syntergite 9+10 well developed, completely divided medially ( Fig. 9 ). Sternite 10 rectangular, weakly sclerotized; narrowly expanded along anterolateral margin of syntergite 9+10. Cercus ovoid fused to syntergite 9+10 ( Figs 9–11 ). Spermatheca well sclerotized, tubular, tapered and sinuous apically ( Fig. 12 ).

Material examined. CHILE. Santiago [= Valparaiso], Marga-Marga , 7.ix.1927, Jaffuel & Pirion (1 ♀, USNM) [33°02′57″S – 71°30′10″W]; Province Santiago [Santiago, metropolis], Quebrada de la Plata , 27.x.1967, el. 510 m, 33°31′S – 70°47′W, E. Schlinger & M. Irwin (1♁, 1♀, CAS).

Remarks. Marga Marga is located in the Valparaíso Region of the Province of Marga Marga, not Santiago Province as stated on the label of the studied specimen. As suggested by Collin (1933), H. nigripennis has a more northerly distribution than H. praesumpta ( Fig. 28 ).

Figures

FIGURE 28. Known distribution of Homalocnemis nigripennis Philippi and H. praesumpta Collin.

FIGURES 1–5. Homalocnemis nigripennis. 1, male, habitus, lateral view; 2, female, habitus, lateral view; 3, male legs, anterolateral view; 4, female thorax and base of abdomen, posterodorsal view; 5, female wing.Abbreviations: bm – basal medial cell, br – basal radial cell, cua – anterior cubital cell, CuA+CuP – anterior branch of cubital vein + posterior branch of cubital vein, M – medial vein, R – radial vein, Sc – subcostal vein.

FIGURES 6–8. Homalocnemis nigripennis, male terminalia. 6, dorsal view; 7, lateral view; 8, ventral view.

FIGURES 9–12. Homalocnemis nigripennis, female terminalia. 9, dorsal view; 10, ventral view; 11, lateral view; 12, spermatheca. Abbreviation: T – tergite.