Middlebury River

Basin:	Otter Creek
State or Province:	Vermont
Country:	USA
Latitude:	43.966025
Longitude:	-73.117211
School:	Middlebury College

The following are the most common invertebrates collected from this stream site.

Trichoptera

Hydropsychidae

Order: Trichoptera (caddisfly)
Family: Hydropsychidae

Common name: net spinning caddisfly
Tied fly: Emergent Sparkle Pupa, Vermont Hare's Ear

This family of net-spinning caddisflies is very abundant at several sites. They are important filtering collectors and are quite common at urban and agricultural sites where particles of organic material can be important food resources. Genus-level identification is possible for mature specimens and we will include the genera we found at your site if possible.

When using the key, some features that are challenging to see are the forked trochantin and the paired sclerites in the folds between segments. Other, more easily seen key features include filamentous gills on the abdominal segments and the sclerotization of the dorsal surfaces of all three thoracic segments. Keep in mind that with smaller or more immature specimens, genus-level ID may not be possible.

Commonly found genera include Cheumatopsyche, Ceratopsyche, and Hydropsyche. Less commonly, we have found Arctopsyche and Potamyia.

Images of the forked trochantin and the paired sclerites.

Limnephilidae

Order: Trichoptera
Family: Limnephilidae

Tied fly: Paul Young's Strawman Nymph, Grouse and Orange

This family of Trichoptera is characterized by having sclerotization on the dorsal surface of the first two thoracic segments. Also, it has a dorsal hump on the first abdominal segment, along with two lateral humps. Here, on a more mature specimen, one can see the prosternal horn characteristic of it and another family Uenoidae. More information on the Uenoidae.

Images of the dorsal hump, the two lateral humps, and theprosternal horn.

Glossosomatidae

Order: Trichoptera
Family: Glossosomatidae

Common name: saddlecase caddisfly

Larvae in this family build domed cases made of small rocks, and are often wider at segment 5. The pronotum is covered in dark, sclerotized plates, but there are either no sclerites on the mesonotum, or the mesonotum is unsclerotized with the exception of a few patches. The anal proleg is broadly joined to segment 9; the anal claw has one or more accessory hooks. The pronotal excision is small (approximately 1/3 anterolaterally) to accommodate the coxae.

Commonly encountered genera include Glossosoma and Agapetus.

Brachycentrus

Order: Trichoptera
Family: Brachycentridae
Genus: Brachycentrus

Common name: The Olive Dun Caddis
Tied fly: Deer Hair Caddis

These larvae are typically found with their legs extended out of their case for feeding. The cases are square in cross section and made of plant materials. Brachycentrus has 2 large sclerites on the metanotum. In fresh samples (preserved for less than one week) these organisms often have a pale green tint; live specimens are a more vivid green.

Ephemeroptera

Heptageniidae

Order: Ephemeroptera
Family: Heptageniidae

Common name: flatheaded mayfly
Tied fly: Light Cahill, Wingless Pale Evening Dun

This family of mayflies can be characterized by their distinctly flattened heads and striking resemblance of the character 'Jack Skellington' from the movie 'The Nightmare Before Christmas.' This family can either have two or three cerci (tails).

Commonly encountered genera include:

Isonychiidae

Order: Ephemeroptera
Family: Isonychiidae

This mayfly has unique long hairs on its forelegs as the main distinguishing characteristic (allowing anyone keying to move through quickly). Carefully observe the limbs because such hair can be matted down and therefore hidden in preserved wet specimens. The body of Isonychia is slim and "minnow-like" when observed dorsally. In specimens we collected, they were commonly brown and substantial in length and width as compared to the very common Baetidae. Some individuals are immature, but upon closer inspection one can see the setae on the forelegs.

Ephemerellidae

Order: Ephemeroptera
Family: Ephemerellidae

Common name: spiny crawler mayflies
Tied fly: Blue-Winged Olive

The mayfly Ephemerellidae is distinguished by the absence of gills on the second abdominal segment; individuals either have gills on segments 3-7 or 4-7. Some may have operculate (plate-like) gills on the fourth segment, though in many the gills are of identical size. The most commonly found genera include Drunella, Ephemerella, and Serratella.

More information on the genera Drunella, Ephemerella, and Serratella.

Ephemeridae

Order: Ephemeroptera
Family: Ephemeridae
Genus: Ephemera

Common name: The Coffin Fly
Tied fly: Dette Coffin Fly

Burrowing mayflies are common in soft sediments in Lake Champlain and also occur in muddy stream pools and in larger rivers. Nymphs have prominent forward-pointing tusks that curve upwards. The fore tibia have lobes or expanded areas that facilitate burrowing. Two genera are common in and around Vermont: Ephemera and Hexagenia; Litobrancha also occurs.

Images of the tusks, and the fore tibia.

More information on Hexagenia.

Baetidae

Order: Ephemeroptera
Family: Baetidae

Common name: Small minnow mayfly
Tied fly: Tiny blue-winged olive

This mayfly has either two or three cerci ("tails") and a unique head shape. Its gills are oval shaped and insert dorsally. Commonly encountered genera include Acerpenna, Baetis and Pseudocloeon.

More information on the genera:

Acerpenna

Baetis

Pseudocloeon

Plecoptera

Perlidae

Order: Plecoptera
Family: Perlidae

Common name: The Golden Stonefly Creeper
Tied fly: Connecticut Curler

This stonefly is characterized by the three pairs of filamentous gills located on the sides of all three thoracic segments. It is distinguished from the family Pteronarcyidae by the absence of gills on the abdominal segments. Often, the thoracic terga are brightly patterned as pictured, though this is not always the case. Another important feature is that the paraglossae and glossae extend different lengths.

Images of filamentous gills and the family Pteronarcyidae.

Genera commonly encountered in this family include Acroneuria, Agnetina, and Paragnetina. Less commonly, we have found Perlesta.

Very rarely encountered genera include Neoperla and Hansonoperla. If you believe you have found either of these, please send a specimen our way!

Peltoperlidae

Order: Plecoptera
Family: Peltoperlidae

Common name: The Little Roach-like Stonefly
Tied fly: Yellow Humpy

Peltoperlidae have stout, roach-like bodies and can have conical gills at the base of legs. Ventral overlapping plates are found on their large thorax. They have a single gill on each side posterior to thoracic segment 3. Peltoperlidae is not covered in the family-level key (Bouchard 2006) used by the Streams Project.

Image of the single gill on each side posterior to thoracic segment 3.

Chloroperlidae

Order: Plecoptera
Family: Chloroperlidae

Common name: The Yellow Sally
Tied fly: Yellow Sally

Stoneflies from the family Chloroperlidae have cylindrical banded abdomens. When observing their mouthparts, the glossae and paraglossae form a three-pronged (open) notch, and their hind wing pads are parallel (not divergent). Cerci have a vertical fringe of hairs pointing away from the abdomen. Setae on the pronotum are found primarily at the corners.

Pteronarcys

Order: Plecoptera
Family: Pteronarcyidae
Genus: Pteronarcys

Common name: The Giant Stonefly
Tied fly: Kaufmann's Black Stone

Pteronarcyidae have branching gills from the bases of their legs as does Perlidae. What distinguishes Pteronarcyidae from Perlidae is the presence of gills on the first two abdominal segments. There are only two genera in this family, but the other, Pteronarcella, is only found in the west/southwest.

Click to see an example of Perlidae or the gills on the first two abdominal segments.

Diptera

Tipula

Order: Diptera
Family: Tipulidae
Genus: Tipula

This genus of Tipula is rather large as compared with other genera. Tipula larvae are generally dark brown and have creeping welts.

Chironomidae

Order: Diptera
Family: Chironomidae

Common name: Nonbiting midge
Tied fly: Griffith's Gnat

Midge larvae tend to be the most common macroinvertebrate at our sites. As with other Diptera, there are no true jointed legs. Chironomidae do have a pair of prolegs at each end and preserved individuals tend to curl into a 'C'. Identification past family requires slide-mounted heads. We have seen philopotamid caddisflies misidentified with the chironomids and we suspect that that happens when samples are being sorted from trays. Under a microscope, six prominent legs can be seen on members of the caddisfly family Philopotamidae.

More information on Philopotamidae.

Simuliidae

Order: Diptera
Family: Simuliidae

Simuliidae appear rather like bowling pins with heads. Relatively speaking, we collect few members of this family and have we have not identified them past family at this point.

Click here for a close up image of the heads.

Athericidae

Order: Diptera
Family: Athericidae

Common name: water snipe flies

Members of the family Athericidae have wrinkled bodies with prolegs on the ventral side. Their mandibles- which can be seen by carefully cutting the head open- move parallel to each other. On the end of their abdomen there are two lobes fringed with setae. Our collections include just the single genus Atherix.

Image of the two lobes of the abdomen.

Odonata

Gomphidae

Order: Odonata
Family: Gomphidae

Common name: clubtail dragonflies

Like other Odonata, members of this family have four wingpads. Like members of the sub-order Anisoptera, the abdomen terminates in five points. What distinguishes Gomphidae from Aeshnidae is the fact that Gomphidae has clubbed antennae.

Image of the four wingpads and the abdomen.

More information on Aeshnidae.

Coleoptera

Dytiscus

Order: Coleoptera
Family: Dytiscidae
Genus: Dytiscus

Adult Dytiscidae have streamlined bodies and hind-legs modified for swimming. They are characterized by the division of the first abdominal segment by the hind coxae. Don't let the paired claws and prominent 'tails' of Dytiscus larva tempt you to think 'stonefly'; these tails are far less segmented than Plecoptera tails.The head and jaws are also unlike those of stoneflies.

Images of the hind-legs, first abdominal segment, 'tails', Plecoptera tails, and the head and jaws.

Psephenidae

Order: Coleoptera
Family: Psephenidae

The true "water penny" is commonly found in the waters sampled. Psephenus has a rounded shape with relatively smooth edge. The false water penny, whose edges are serrated, has a more oval appearance. The gills on the ventral surface are found only in the true water pennies.

Megaloptera

Corydalidae

Order: Megaloptera
Family: Corydalidae

Common name: Dobsonfly; Hellgrammite

Members of the family Corydalidae share some superficial commonalities with Trichoptera, but on careful inspection one can see the two pairs of anal claws that help place it in the order Megaloptera. The size of mature larvae is impressive; specimens from some genera exceed 8 cm in length. The abdominal segments have ribbon-like gills on the lateral portions. The mouth has mandibles that are serrated and used for biting prey. They can be confused with the more slender whirligig beetle larvae; whirligig larvae also have simpler jaws. Nigronia is the genus we most frequently encounter.

Middlebury River

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