Lackawanna River True flies
Order: Diptera
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Lackawanna River True flies |
Organisms within the order Diptera are collectively known as true flies. Five families of true flies are represented here. The Dipteran order is one of the largest insect orders.
Crane fly larvae are segmented and worm-like. They can be found in a wide variety of colors, including white, brown, and green. Tipula organisms are almost translucent, so you can see the insides of the organism move when it crawls. The larvae have a soft, fleshy appearance and very short tentacles at one end which can be seen more easily if the larvae is in water or is gently squeezed. Tipula larvae are pollution intermediate organisms that burrow into packs of leaves and sticks, primarily along the River's shore. They shred the plant material into smaller pieces, sometimes in the process eating other macroinvertebrates. Antocha larvae are found more in fast water on rocks and logs, collecting and feeding on small plant material.
Tipula larvae are common throughout the River, except for the downstream reach from Old Forge to the confluence. Their large size make
them easy to spot and they can be very common in areas where leaves and sticks accumulate. Antocha larvae are not nearly as common and seem to be restricted to more
upstream reaches of the River, from the Mid Valley upstream.
Family: Tipulidae (crane flies)
Key features:
no legs
worm like and plump
small tentacles at one end
size range: Tipula 1/2-2 1/2";
Antocha 1/16-1/4"
 | Family: Tipulidae Genus: Tipula |
 | Family: Tipulidae Genus: Antocha |
Family: Chironomidae (midges or chironomids)
Key features:
no legs
usually very small and slender
small proleg below the head
small tentacles at other end
size range: 1/16-1/4"
Midge larvae are usually brown and white in color, though some have a distinct red color. The best way to identify these larvae is by their small size and spastic squirming action in water. They can be found under stones or buried into the sediment, feeding on tiny plant particles and bacteria. Some make small silk-like tubes that they live in.
As a group, midge larvae are considered pollution tolerant organisms. They are widespread throughout the River and are one of the few
macroinvertebrates that are able to survive within the River downstream of Old Forge. Red midges are especially pollution tolerant and are found within the lower reach. Some midges are
more pollution sensitive and are found within upper reaches.
 | Family: Chironomidae |
 | Family: Chironomidae |
Family: Simuliidae (black flies)
Key features:
no legs
quite small
bulbous at one end and constricted in the middle
size range: 1/16-1/4"
Black fly larvae use their bulbous end to attach themselves to stones and other material, usually in the faster flowing areas of a riffle. They may be found in groups and will often curl into a "u" shape when pulled off and held in the hand. Most larvae are grey or brownish in color. Female adult black flies are among the most important insect pests of humans and animals in many parts of the world, because of the toxic and allergic properties of their bite. The larvae use "fans" attached to their heads to filter small plant particles out of the water column, which they then eat.
Black fly larvae are pollution tolerant organisms. They are not very common in the River, however, they have been found throughout its reach.
Large populations of black fly larvae usually are not allowed to develop, because of the potential for health problems from the adults. The State of Pennsylvania has an eradication program for
populations that get too large and could potentially cause health problems in urban areas.
 | Family: Simuliidae Genus: Prosimulium |
 | Family: Simuliidae Genus: Simulium |
Families: Athericidae and Empididae (dance flies)
Key features:
no legs
small head capsule at one end
small tentacles at other end
size range: Athericidae, 1/16-1/4"; Empididae, 1/16-1/8"
Organisms within these two Families are usually quite small and can be found in areas where sediment has been deposited, along a stream's bank or in a pool. Both are predators on other macroinvertebrates; Atherix pierce their prey and suck the juice out, while Hemerodromia eat their prey whole.
Atherix organisms are considered pollution sensitive, while Hemerodromia are more pollution intermediate organisms. Atherix
are more common in the River, primarily from the Mid Valley upstream. Hemerodromia has also been found within more upstream reaches, however, they are rare.
 | Family: Athericidae Genus: Atherix |
 | Family: Empididae Genus: Hemerodromia |