Snipe Island Brook

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.  Chironomids 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 the philopotamids.

ORDER: Ephemeroptera
FAMILY: Heptageniidae
GENUS: Epeorus. 

A mayfly with two 'tails'!  This family of mayflies has distinctly flattened heads, and this particular genus has two tails and a unique gill arrangement.
NABS

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: Ephemeroptera
FAMILY: Baetidae 
GENUS: Baetis 

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

ORDER: Plecoptera
FAMILY: Leuctridae
GENUS: Leuctra

Among our most common stoneflies, this family 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: 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: Ephemeroptera
FAMILY: Heptageniidae
GENUS: Heptagenia

Heptagenia are easily characterized by their flat head. The claws have just one basal tooth and no denticles (serrated edges).  The gill on abdominal segment 7 has multiple fibrils at is base (thread-like structures) and has a single tooth on its claws but is smooth otherwise.  Gills on segment 7 are similar to those on all other segments, but may be smaller in size.

ORDER: Ephemeroptera 
FAMILY: Leptophlebiidae

Leptophlebiidae are distinguished from the more common genus Baetis by a somewhat flattened body and forked elongate gills. SMC

© Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Trichoptera
FAMILY: Glossomatidae
GENUS: Glossosoma

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 no sclerites on the mesonotum. 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.

©US EPA

ORDER: Ephemeroptera
FAMILY: Leptophlebiidae
GENUS: Paraleptophlebia

 Leptophlebiidae have forked, tufted, or fringed gills.  Paraleptophlebia  typically have labrums less than 1/2 as wide as head anteriorly, which is considered "shallow." There are minute spinules present on posterior margins of abdominal terga 1-10. EPA

ORDER: Diptera
FAMILY: Simuliidae

What's not to like about blackflies?  Our second most common dipteran.  Rather like a bowling pin with hands attached at the head end.  We have not identified them past family at this point, but it is in the long-term plan.
NABS

ORDER: Coleoptera 
FAMILY: Elmidae
GENUS: Optioservus

The larvae of Optopservus have a closed 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 feature observable in the dorsal view. SMC