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Macroinvertebrates home

Streams project

 

Miller's Run Tributary

These are the most common macroinvertebrates identified from samples from Miller's Run Tributary.

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: 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: Ephemeroptera
FAM
ILY: Heptageniidae
GEN
US:
Epeorus

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


NABS
ORDER: Trichoptera
FAMILY: Brachycentridae 
GENUS: Brachycentrus

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.

 

ORDER: Ephemeroptera
FAM
ILY: Heptageniidae

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 Epeorus, Heptagenia, Maccaffertium, and Rhithrogena.

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: 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: 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: 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: 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. SMC

 

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: Alloperla

Chloroperlids from this genus are characterized by a fringe of intrasegmental setae on their cerci.


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.

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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