Phenology of aquatic dance flies (Diptera: Empididae: hemerodromiinae) along a stream in Southern California

From May 1996 through April 1998, adult flies in the subfamily Hemerodromiinae were systematically collected with sweep nets along a first-order mountain stream in Southern California. Four genera and eight species were included in the 897 specimens collected. About 78% of the collection was Neoplasta parahebes MacDonald & Turner, which was found as early as March and as late as December with a maximum abundance in June and July. Sex ratios for N. parahebes (55% females) were consistent with other empidid studies. Neoplasta scapularis (Loew) and Metacheta albipes Walker were male dominated (68% and 67% males respectively), with a bimodal seasonal distribution (early summer and fall) that suggested a migratory pattern. Chelifera lovetti Melander appeared only in the spring while Chelifera neangusta MacDonald was found only in the fall.