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Macroinvertebrates home

Streams project

 

Roaring Brook (FMR_RoaBrk_238)

These are the eight most common macroinvertebrates identified from samples from Roaring Brook.

Click on images to zoom in. 

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 femora which bears a single hair (seta). SMC

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: 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: 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: 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: Coleoptera
FAM
ILY: Psephenidae
GEN
US:
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. SMC

Another genus encountered in this family is Ectopria.

 

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. SMC

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Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Trichoptera
FAMILY: Glossomatidae

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.


 

ORDER: Trichoptera
FAMILY: Hydropsychidae
GENUS: Hydropsyche

Hydropsyche share most characteristics with Ceratopsyche, including the sclerites in the intersegmental folds. Hydropsyche are distinguished from Ceratopsyche by the presence of scale hairs and minute spines on the three most posterior abdominal segments. SMC

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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