Stilpon

Loew, 1859

Stilpon is a of small predatory flies in the Hybotidae, Tachydromiinae. The Nearctic fauna comprises 13 recognized , including nine described by Cumming (1992), classified into three informal species groups: S. divergens, S. graminum, and S. varipes. The genus exhibits wing polymorphy in some species, with both and forms documented in S. graminum, S. nubilus, and S. subnubilus.

Stilpon by (c) Katja Schulz, some rights reserved (CC BY), uploaded by Katja Schulz. Used under a CC-BY license.

Pronunciation

How to pronounce Stilpon: /ˈstɪlpɒn/

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Identification

Nearctic are distinguished using characters of the male and female terminalia; of these structures have been clarified relative to other Empidoidea. A key to the 13 Nearctic species is available. Wing polymorphy complicates visual identification in some species pairs, as wing size and coloration vary between and forms.

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Distribution

Documented from the Nearctic region (North America), with type localities across Canada (Saskatchewan, Ontario, New Brunswick implied) and the United States (Alabama, New York, Georgia, New Hampshire, Tennessee, Massachusetts). Palearctic records include France (S. subnubilus), Denmark, Norway, and Sweden.

Similar Taxa

CrossopalpusStilpon obscuripes (Adams) was transferred to Crossopalpus as C. obscuripes comb. nov., indicating historical confusion between the .
Other TachydromiinaePhylogenetic relationships within Tachydromiinae are discussed; Stilpon monophyly is justified but precise sister-group relationships require further study.

More Details

Taxonomic history

Stilpon pectiniger Melander was synonymized with S. varipes Loew. Stilpon pleuriticus Melander was excluded from the . Stilpon demnatensis Vaillant is considered a . Lectotypes were designated for S. pauciseta Melander and S. pectiniger Melander.

Wing polymorphy

Wing polymorphy (presence of both fully-winged and reduced-wing individuals) is now documented in S. graminum, S. nubilus, and S. subnubilus. This phenomenon complicates based on wing characters alone.