Homalocnemis praesumpta Collin, 1933

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 : 172-174

Homalocnemis praesumpta Collin, 1933

( Figs 13–27 , 28 )

Homalocnemis praesumpta Collin, 1933: 31 , figs. 6b, c. Type-locality: Ancud, Chiloé Is., Chile.

Syntypes. Four males, one female ( NHMUK); one male ( OUMNH). See Pont (1995: 135) for label details .

Distribution. Chile: Región de La Araucanía: Malleco Province (Termas de Tolhuaca, Sierra de Nahuelbuta); Región de Los Lagos: Osorno Province (PN Puyehue, Termas Aguas Calientes), Llanquihue Province (Ensenada, Puerto Varas); Chiloé Province (Ancud, Chiloé I.) ( Fig. 28 ).

References. Stuardo, 1946: 104 (cat.); Smith, 1967: 9 (cat.); Chvála, 1991: 13 (com.); Pont, 1995: 135 (typ.); Yang et al., 2007: 280 (cat.).

Diagnosis. In addition to features in the key, this species is distinguished by the absence of a digitiform epandrial process, male cerci fused to surstylus posterolaterally and female sternite 8 greatly enlarged, and apex deeply bilobed.

Redescription. Wing length: 4.4–6.1 mm. Male ( Figs 13–21 ). Predominantly black with mesopleuron and coxae gray pruinose ( Fig. 13 ). Front of scutum entirely dull black; prescutellar depression with broad, rectangular pruinose patch. Palpus with long blackish setae ( Fig. 14 ). Wing infuscate, anal lobe weakly developed ( Fig. 15 ). Vein R 2+3 gently upcurved distally, ending after level of branching of vein R 4+5. Section between veins R 2+3 and R 4 shorter than section between veins R 4 and R 5 ( Fig. 15 ). Hind tarsomere 1 not swollen. Tergite 8 half-length of respective sternite ( Figs 16, 17 ), narrowed medially; sternite 8 with desclerotized or depigmented medial area ( Fig. 17 ); remaining pregenital sclerites unmodified. Terminalia highly sclerotized. Epandrial lamellae broadly quadrate, somewhat inflated, fused narrowly along dorsal bridge; without subapical process ( Fig. 18 ). Cercus laminar, narrowly tapered anteriorly; broadly fused to surstylus posterolaterally ( Fig. 18 ). Hypoproct membranous, clothed in minute setulae ( Fig. 18 ). Subepandrial sclerite broadly V-shaped, extending as bacilliform sclerites to surstylus; surstylus fused broadly with epandrium ( Fig. 18 ). Hypandrium with gonocoxal apodeme well developed, expanded horizontally; gonocoxal apodemes united dorsally by upright phallic plate ( Fig. 19 ); phallic plate tapered dorsally to base of subepandrial sclerite, opposite dorsal bridge of epandrial lamellae. Postgonites fused dorsally across hypandrium into elongate, upright digitiform process, rod-shaped with rounded apex ( Fig. 19 ). Apex of hypandrium articulated with phallus ( Fig. 19 ). Phallus with paired, short, acute lateral projections and deeply forked apex ( Fig. 20 ). Ejaculatory apodeme slender, elongate, positioned within hypandrium, separated from base of phallus ( Figs 19, 21 ).

Female ( Figs 22–27 ). Same pattern of color as male ( Fig. 22 ). Sternite 8 paired, narrowly connected ventrally ( Fig. 24 ), enlarged basally, elongate, posteroventrally directed into projecting lobes; clothed in distinct apical setae ( Fig. 23 ). Syntergite 9+10 absent. Sternite 10 ( Figs 25, 26 ) triangular in dorsal view, with narrow, darkly pigmented anterior margin; dark band loosely connected or separated from pair of thinly sclerotized medial plates. Genital fork not observed, probably not sclerotized. Cercus ovoid ( Figs 24–26 ). Spermatheca well sclerotized, subspherical ( Fig. 27 ).

Material examined. CHILE. Región de La Araucanía: Province Malleco, Termas de Tolhuaca [38°14′06″S – 71°43′58″W], 1989, L. Peña (1♁, CNC) ; Región de Los Lagos: Prov. Osorno, Parque Nacional Puyehue, Termas Aguas Calientes, 40°44′S – 72°19′W, 440 m, 14–31.i.2017, sweeping, V.C. Silva & D.S. Amorim (1♁, MZUSP; 1♁, INPA) ; Prov. Llanquihue, Volcán Osorno, 322 m, 41°10′09″S – 72°30′51″W, 8.ii.2011, sweeping, D.S. Amorim (1♁, 1♀, MNNC; 1♁, 1♀, INPA) ; [Province Malleco], Sierra de Nahuelbuta , W. of Angol, 1200 m, 3.i.1951, leg. Ross & Michelbacher (1♀, CAS) [37°49′40″S – 72°59′27″W] ; [Province Llanquihue], 8 miles W. of Puerto Varas, 16.i.1951, leg. Ross & Michelbacher (1♀, CAS) [41°19′27″S – 73°08′41″W].

Figures

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

FIGURES 13–15. Homalocnemis praesumpta, male. 13, habitus, lateral view; 14, head, anterolateral view; 15, wing. Abbreviation: R – radial vein.

FIGURES 16–21. Homalocnemis praesumpta, male terminalia. 16, apex of abdomen, lateral view; 17, tergites and sternites 5–8, tergites in dorsal view; 18, epandrium, dorsal view; 19, genitalia, lateral view; 20, hypandrium and phallus, posterior view; 21, ejaculatory apodeme, anterior view.

FIGURES 22–27. Homalocnemis praesumpta, female. 22, habitus, lateral view; 23, apex of abdomen, lateral view; 24, tergites and sternites 4–8 and cerci, tergites in dorsal view; 25, sternite 10 and cerci, ventral view; 26, idem, lateral view; 27, spermatheca.