Sphaerops Philippi, 1865

Schlinger, Evert I., Gillung, Jessica P. & Borkent, Christopher J., 2013, New spider flies from the Neotropical Region (Diptera, Acroceridae) with a key to New World genera, ZooKeys 270, pp. 59-93 : 63

Sphaerops Philippi, 1865

Diagnosis.

Body shape not arched; coloration non-metallic. Head width slightly less than thorax width; nearly spherical in shape; ocellar tubercle raised and rounded with three ocelli; postocular ridge and occiput rounded; posterior margin of eye rounded; eye sparsely pilose with minute setae (not more than 4 × length of single ommatidium); eyes either contiguous above antennal base or with antennal base adjacent to dorsal eye margin, contiguous below antennal base; palpus absent; proboscis length greatly reduced with sparse pile; antennae located near or adjacent to ocellar tubercle; flagellum stylate, apex with terminal seta(e); scapes not fused together; postpronotal lobes not enlarged or contiguous medially; antepronotum narrow; subscutellum enlarged; legs not elongated; tibial spines absent; pulvilli present; wing markings and microtrichia absent. Costal vein ending near wing apex; costal margin straight; humeral crossvein absent; R1 inflated at pterostigma; radial veins straight, veins R4 and R5 present as single fused vein; crossvein 2r-m present between M1 and R4+5, bisecting cell r4+5, basal portion of cell narrow elongate; two M veins present, not reaching wing margin; discal cell closed; cell m3 absent; CuA1 joining M3; anal lobe well developed; alula well developed. Abdomen greatly rounded, inflated, tergites smooth.

Comments.

Sphaerops is an endemic Chilean genus than can be readily differentiated from all other acrocerine genera based on the sparsely pilose eyes, wing vein A1 fused to CuA2 and the bulbous genitalia. Sphaerops is also unique in exhibiting the widest range in size variation within acrocerids. The genus shows remarkable similarity to the Chilean endemic genus Villalus , sharing numerous characteristics such as having the antennae placed away from the ocellar tubercle (except in Sphaerops micella ) and vein R4+5 present as a single, unforked, vein. Evert I. Schlinger has reared numerous Sphaerops individuals and reported that the mature larvae fed externally on spiders for up to three weeks. This type of development is unique as all other acrocerids with known larval habits are endoparasitoids until emerging to pupate ( Schlinger 1987).

Key to species of Sphaerops