Malletts Creek

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Malletts Creek
Stream code:	LCD_MllttsCrk_616
Basin:	Lake Champlain
State or Province:	Vermont
Country:	USA
Latitude:	44.63559
Longitude:	-73.086612
School:	Milton High School

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

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.

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.

Optioservus

Order

Coleoptera

Family

Elmidae

Genus

Optioservus

The larvae of Optioservus have open coxae, as determined by the straight definition between segments on the ventral side of the pronotum.

The adult Optioservus have a compact appearance, especially the head and thorax. There are also dorsal ridges and a characteristic diamond-shaped sutellum observable in the dorsal view.

Images of the straight definition between segments, the dorsal ridgesand the diamond-shaped scutellum.

Stenelmis

Order

Coleoptera

Family

Elmidae

Genus

Stenelmis

The larvae of Stenelmis, as in Ordobrevia, have a sternum on the ventral side of the pronotum. The main difference between the two genera is in the antennae the second segment is less than twice as long as the first in Stenelmis.

The adult Stenelmis has a clear separation between the thorax and abdomen as well as a more distinctly separate head as compared to other genera.

Click here to see pictures of the sternum and antennae-

Psephenus

Order

Coleoptera

Family

Psephenidae

Genus

Psephenus

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.

Another genus encountered in this family is Ectopria.

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.

Ceratopogonidae

Order

Diptera

Family

Ceratopogonidae

Common name

biting midges

Members of this family look like very straight Chironomidae. They are very long and thin with a distinct head capsule and no prolegs. Some in the lab call them 'bamboo sticks' with eyes.

Image of the distinct head capsule.

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.

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.

Dicranota

Order

Diptera

Family

Tipulidae

Genus

dicranota

Dicranota can be distinguished by the two tails and their comb feet. There are usually 5 pairs of prolegs on the abdomen with combs on them. In addition, the posterior portion of the abdomen often has a slight swelling.

Image of the prolegs.

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.

Baetis

Order

Ephemeroptera

Family

Baetidae

Genus

Baetis

Common name

The Little Olive

Tied fly

Sawyer Pheasant Tail Nymph

This mayfly has three "tails" and a unique head shape. Its gills are oval shaped and insert dorsally. More mature nymphs have long, dark wing pads.

Image of the long, dark wing pads.

Chimarra

Order

Trichoptera

Family

Philopotamidae

Genus

Chimarra

Chimarra are distinguished from the other Philopotamidae by a prominent asymmetrical notch in the frontoclypeus as well as a prominent process on the femur which bears a single hair (seta).

Images of the asymmetrical notch and prominent process.

Dolophilodes

Order

Trichoptera

Family

Philopotamidae

Genus

Dolophilodes

Dolophilodes stands out in the Philopotamidae family due to its slightly asymmetrical frontoclypeus on the anterior margin and its distinguishable projecting foretrochantin.

Images of the slightly asymmetrical frontoclypeus, and the projecting foretrochantin.

Pseudocloeon

Order

Ephemeroptera

Family

Baetidae

Genus

Pseudocloeon

Tied fly

Bluewinged Olive

Mayflies in this genus have a distal lobe on their antennal scapes, and the second segment of labial palps has an expanded medial process. Villopores are absent on legs.

Click to see the antennal scapes. The dorsal and ventral views can be seen here.

Epeorus

Order

Ephemeroptera

Family

Heptageniidae

Genus

Epeorus

Common name

The Quill Gordon

Tied fly

Quill Gordon

This is the only Heptageniidae genus present in this area with two tails!

Leptophlebiidae

Order

Ephemeroptera

Family

Leptophlebiidae

Common name

pronggill mayfly

Leptophlebiidae are characterized by a somewhat flattened body and forked elongate gills. Commonly found genera include Habrophlebia and Paraleptophlebia.

Image of the forked elongate gills.

Siphlonuridae

Order

Ephemeroptera

Family

Siphlonuridae

Genus

Siphlonurus

Common name

The Gray Drake

Tied fly

Gold-ribbed Hare's Ear

This family has gills on all abdominal segments. The labrum does not have a deep notch, and maxillae do not have pectinate spines. They have posterolateral spines on their last abdominal segment.

Click to view the spines on the last abdominal segment, unlike those found in Baetidae.

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.

Leuctra

Order

Plecoptera

Family

Leuctridae

Genus

Leuctra

This family of stonefly is fairly slender by stonefly standards. The divergent wing pads are a helpful characteristic. Leuctridae are similar in overall shape to the Capniidae; however, Leuctridae often do not have pleural folds. If they are present, they only extend from abdominal segments 1-7. Leuctra are recognized by abdominal terga with posterior fringes of short hairs and last few segments with longer hairs.

Image of the divergent wing pads.

Paragnetina

Order

Plecoptera

Family

Perlidae

Genus

Paragnetina

Paragnetina have 3 ocelli (spots) on the back of their head. Like the other Perlidae, there are highly branched gills located on the sides of the thorax. The dorsal sides of the abdominal segments have small hairs on lateral portions but not in the center of the segment.