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Macroinvertebrates home

Streams project

 

Halls Brook (CTJW_ HllsBrk_713)

These are the most common macroinvertebrates identified from samples from Halls Brook by Snake Road in Newbury, Vermont.

Click on images to zoom in. 

ORDER: Ephemeroptera
FAMILY: Baetidae 
GENUS: Baetis 

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. SMC

ORDER: Diptera
FAMILY: Chironomidae

 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 family Philopotamidae.

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. NABS

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 scutellum observable in the dorsal view.
SMC

 

ORDER: Plecoptera
FAMILY: Perlidae
GENUS: Agnetina

The Agnetina has a rounded abdomen that appears to striped. The key defining characteristic is the three ocelli on the dorsum of the head (3 black dots at joint with the prosternum). Like other Plecoptera, it has 2 tails and 2 claws on its tarsi. SMC

This stonefly is characterized by the filamentous gills located in the "armpits". Another important feature is the paraglossae and glossae extending different lengths. The occiput has a transverse row of evenly spaced little hairs. Agnetina has another row of evenly spaced hairs on the posterior edge of abdominal segment 7.

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.


ORDER: Trichoptera
FAMILY: Hydropsychidae

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

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.

ORDER: Trichoptera
FAMILY:
Hydropsychidae
GENUS: Ceratopsyche

Ceratopsyche has a forked foretrochantin. The foretrochantin is the projection at the uppermost portion of the foreleg. The leg may need to be pulled away from the body to expose this feature.

Ceratopsyche have a large pair of sclerites underneath the prosternum. Note: the large single sclerite is the prosternal plate. SMC

 

 

ORDER: Diptera
FAMILY: Simuliidae

Simuliidae appear  rather like bowling pins with heads.  We have not identified them past family at this point, but it is in the long-term plan.

ORDER: Plecoptera
FAMILY: Peltoperlidae
 

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 posterior to thoracic segment 3.  Peltoperlidae is not covered in the family-level key (Bouchard 2006) used by the Streams Project.

ORDER: Trichoptera
FAMILY:
Hydropsychidae
GENUS: Cheumatopsyche

Cheumatopsyche has a forked foretrochantin (as does Ceratopsyche). The foretrochantin is the projection at the uppermost portion of the front leg closest to the head. The leg may need to be pulled away from the body to expose this feature.

Cheumatopsyche have a small or inconspicuous pair of sclerites under the prosternal plate that are difficult to see.  Contrast that with the larger pair of sclerites found on CeratopsycheTo access sclerites, it's best to gently pull the pronotum and mesonotum in opposite directions. Note: the large single sclerite is the prosternal plate.

Cheumatopsyche have only 2 types of hair on the abdomen: long thin plain hairs and thicker club hairs, which are narrow close to the body and widen out at the distal end. Paired sclerites on the ninth abdominal segment are notched. SMC

ORDER: Ephemeroptera
FAM
ILY: Heptageniidae
GEN
US:
Epeorus

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

ORDER: Coleoptera
FAMILY: Elmidae
Genus: Dubiraphia
 

The larvae of this genus are distinguished by the last abdominal segment, which is very elongated.

Adults of this genus usually have prominent longitudinal markings on their elytra and, like adult Optioservus, have a fringe of tomentum on their anterior tibia.

ORDER: Coleoptera
FAMILY: Elmidae
Genus: Promoresia
 

So far we have only encountered Promoresia larvae; as soon as an adult becomes available to us, this template will be revised! The defining characteristic of the larvae is the prominent ridge along the back of the abdomen.

ORDER: Diptera
FAMILY: Tipulidae
GENUS: Antocha

This small Diptera in the cranefly family is quite common.  It is distinguished from most other dipterans we found by the 'creeping welts' that appear as prominent dark stripes along the abdomen.  The dark head is usually partly exposed; however, it can be pulled back into the thoracic cavity during preservation.
NABS

ORDER: Ephemeroptera
FAMILY: Ephemerellidae


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.

Commonly encountered genera include Drunella, Ephemerella, and Serratella.

 

ORDER: Ephemeroptera
FAMILY: Heptageniidae
Genus: Maccaffertium
 

This genus of Heptageniidae is distinguished by its gills on the seventh abdominal segment, which are reduced to slender filaments. Gills on segments 1-6 are truncated.


ORDER: Plecoptera
FAMILY: Chloroperlidae
GENUS: Sweltsa
 

Chloroperlidae have bodies roughly as wide as their pronotum. Their mouthparts look like this, with their paraglossae are much longer than their glossae and a deep notch in the labium. The genus Sweltsa is characterized by having dark clothing hairs at the base of the coxae.

ORDER: Trichoptera
FAMILY: Lepidostomatidae
 

These have lateral humps on the first abdominal segments, but lack a dorsal hump. The dorsa of the first two thoracic segments are sclerotized. They are frequently found in four-sided cases made of square pieces of detritus.

ORDER: Trichoptera
FAMILY: Rhyacophilidae
GENUS: Rhyacophila

In our lab, Rhyacophila is known as the "Michelin Man" due to its large banded body. It has a very obviously checker-patterned head. It also has a terrifying anal claw which has large accessory hooks. SMC

Hexatoma sp. Tipulidae - photo by Wayne Davis USEPA
US EPA

ORDER: Diptera
FAMILY: Tipulidae
GENUS:
Hexatoma

This Tipulidae can be identified by the swollen 7th abdominal segment.

ORDER: Diptera
FAMILY: Tipulidae
Genus: Limnophila
 

This genus of Tipulidae has a spiracular disk with 4 lobes fringed with long hair. Out of the other end, simple, non-jointed mandible project even when the head is retracted (pictured in the lower left area of the main image). The head, which can be viewed by cutting away the skin, is not extensively sclerotized. Rather, the sclerites are long, slender rods.

The images are not a substitute for keying, but should serve as an aid in identifying common macroinvertebrates in samples.

Feedback - Partner schools: send us specimens not included above.  Taxonomists: click to email: Declan McCabe
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