Deerfield River North Branch (DR_NBDrfld_2067)

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: Chloroperlidae
GENUS: Alloperla

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

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: 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: Trichoptera
FAMILY: Uenoidae
GENUS: Neophylax

Neophylax are characterized by having a sclerotized pronotum and mesonotum. a rather stout Trichoptera. The head is scrunched in between the arms, and the anal hooks are connected directly to the bottom of the abdomen. On the ventral surface of the abdominal segments, one can see darkened ovals, known as the chloride epithelia. Like the Limnephilidae, they have a prosternal horn, though it can sometimes be small. Also, they have a dorsal hump and two lateral humps on the first abdominal segment- be careful! Often times, these features can be squished down or damaged in the sampling process.

The feature that distinguishes Uenoidae from Limnephilidae is the mesonotum: on either side of the midline, the anterior margin is notched.

Because our samples were taken in summer, we found large numbers of Neophylax pre-pupae. We anticipate that there will be fewer present in the streams in late September and many of those sampled will be at the pupal or adult stage.  Samples taken in October would tend to have more empty cases. SMC

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

© Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Trichoptera
FAMILY: Brachycentridae 
GENUS: Micrasema

These larvae are typically found with their legs extended out of their case for feeding. The cases are circular in cross section and made of sand grains.

© Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Ephemeroptera
FAMILY: Ephemerellidae
GENUS: Ephemerella

Mayflies in this genus have long intersegmental setae on their cerci that extend laterally and may or may not have whorls of spines at the end of each segment of their cerci. Their maxillary palps are well-developed.

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: 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.