Solitary Midges
Female thaumaleid on a leaf.
Solitary midges, trickle midges or just thaumaleids (my preference) are names for a group of unique, uncommon, small flies. Because of their unfamiliarity, most information on the Internet is found by searching for the family name Thaumaleidae. The primary purpose for this page on my website is because there are very few photos of this group of insects in their natural habitat on the Internet. These photos and others were taken during my research in the San Francisco Bay area. It is time to make the photos available to those who would have an interest in seeing them.
Although thaumaleids are considered uncommon, they really are not when searched for in their unique habitats along streams, seeps and waterfalls in rocky areas. These are small insects -- the adults are about 2-3 mm in length ant the larvae are about 7-10 mm in length. The immatures are found in habitats of permanent splash, spray or seeps of cool water that forms a thin film of water on the rock surface (hygropetric habitats). Also, they seem to prefer mostly shaded areas and a high relative humidity. Adult thaumaleids can be found at the larval site and around adjacent vegetation.
The color photos were taken at a site of a species new to science in a wooded canyon near San Jose, California. The thaumaleid was named Thaumalea santaclarensis (no common name). The location of the larvae is the splash and seepage zones. They feed on diatoms and detrital materials found in the habitat. The black and white photo is of a different site in the Santa Cruz Mountains.
Although thaumaleids are considered uncommon, they really are not when searched for in their unique habitats along streams, seeps and waterfalls in rocky areas. These are small insects -- the adults are about 2-3 mm in length ant the larvae are about 7-10 mm in length. The immatures are found in habitats of permanent splash, spray or seeps of cool water that forms a thin film of water on the rock surface (hygropetric habitats). Also, they seem to prefer mostly shaded areas and a high relative humidity. Adult thaumaleids can be found at the larval site and around adjacent vegetation.
The color photos were taken at a site of a species new to science in a wooded canyon near San Jose, California. The thaumaleid was named Thaumalea santaclarensis (no common name). The location of the larvae is the splash and seepage zones. They feed on diatoms and detrital materials found in the habitat. The black and white photo is of a different site in the Santa Cruz Mountains.
Thaumaleid habitat located behind handle of net.
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Female thaumaleid on the rock surface with a flowing water film.
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Three thaumaleid larvae (identified with arrows).
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Searching for thaumalids behind a waterfall.
Investigations in the 1970s-90s have contributed greatly to the knowledge base of these insects. More species were found in the region and I am pleased that one was named Thaumalea brothersi. Recently, the generic name was revised to Androprosopa.
References:
- Brothers DR. 1972. A new species of Thaumalea from California (Diptera:Thaumaleidae). Pan-Pac. Ent.48:121-122.
- Brothers DR. 1973. The thaumaleids of the South San Francisco Bay Area with biological notes (Diptera:Thaumaleidae). M.A. Thesis. California State University - San Jose. 51 pp.
- Arnaud Jr PH, Boussy IA. 1994. The adult Thaumaleidae (Diptera:Culicomorpha) of Western North America. Myia 5:41-152.
- Gillespie JM, Barr WF, Elliott ST. 1994. Taxonomy and biology of the immature stages of species of Thaumalea occurring in Idaho and California (Diptera:Thaumaleidae). Myia 5:153-193.