Eulonchus halli Schlinger, 1960

Borkent, Christopher J., Gillung, Jessica P. & Winterton, Shaun L., 2016, Jewelled spider flies of North America: a revision and phylogeny of Eulonchus Gerstaecker (Diptera, Acroceridae), ZooKeys 619, pp. 103-146 : 110-112

Taxon classification Animalia Diptera Acroceridae

Eulonchus halli Schlinger, 1960 Figs 2, 16B, 17A, 18A, 19A

Eulonchus halli Schlinger, 1960: 418

References.

Arnaud 1979: 203 (holotype depository); Schlinger 1981: 576 (figs); Poole 1996: 36 (checklist).

Common name.

Hall’s Sapphire.

Diagnosis.

Proboscis curved and extending beyond abdomen apex (but shorter than wing length), ocellar tubercle bifurcate; calypter margin pale; legs dark brown-black; abdomen dark brown with reddish metallic hue; extensive white pile on thorax and as bands on abdomen.

Redescription.

Body length: 9.8-12.0 mm, Wing length 8.0-10.6 mm. Head. Flagellum dark brown, scape and pedicel brown; male flagellum cylindrical, shorter than head height; clypeus elongate, extending beyond oral cavity, shape rounded with raised ridge dorsally, surface glossy black-brown with sparse pubescence; labial palp brown, extending anteriorly beyond proboscis at point of attachment; margin of oral cavity (parafacial) finely pubescent, lacking pile; proboscis length extending to middle of abdomen; ocellar tubercle bifurcate, apices narrowly digitate and sub-parallel, tubercle height taller than width, median ocellus greatly reduced; occiput metallic blue or metallic purple, occipital pile densely white. Thorax. Metallic green, metallic blue or metallic purple in colour, setal pile white; coxae black with metallic blue sheen; femora dark brown, apices white; tibia brown; tarsi brown; calypter margin yellow or light brown, membrane translucent; haltere entirely dark brown. Abdomen. Metallic green, metallic blue violet or black with metallic green sheen, vestiture white, dominant setae erect, other pile posteriorly directed, marginal band of denser setae on T3-4. Male genitalia (Figs 17A, 18A, 19A). Epandrium rectangular, wide at the apex, with posterior margin concave; gonocoxite deeply emarginate along anterior margin, fenestrae lacking; aedeagus thinned at the apex, only slightly sclerotized.

Type material examined.

Holotype male, CAS, "Riverside/ Cal. Mar 7, 34" [white]; "Timberlake/ Coll." [white]; "on Cryptantha / intermedia " [white]; "HOLOTYPE/ Eulonchus / halli / ♂ Schlinger" [orange]; "Genitalia 51-3-id/ Dissection No./ by E.I. Schlinger" [white]; "California Academy/ of Sciences/ Type No. 6392" [white]; “IMAGE” [green]; " CAS/ Dec-07" [green]; specimen condition: good, proboscis, right flagellum and right front leg broken off and glued to a paper triangle on pin with specimen. Body length: 10.2 mm, Wing length: 9.2 mm.

Other material examined.

Listed in Table 3 (Suppl. material 1).

Distribution

(Fig. 20). Nearctic: Southern California (USA) to Baja California (Mexico).

Ecology.

Schlinger (1960) notes that this species has a relatively short adult flight period (ca. six weeks) during spring and has a feeding preference on Cryptantha intermedia flowers (Table 2).

Biology.

The larval host for this species is unknown.

Comments.

Eulonchus halli is a distinctive species that can be distinguished by the dark leg and body colouration, erect white thoracic and abdominal pile, raised bifurcate ocellar tubercle, and a curved proboscis that is shorter than the body length.