Deerfield River North Branch

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.

© Donald S. Chandler / Discover Life

ORDER: Plecoptera
FAMILY: Chloroperlidae
GENUS: Alloperla

Chloroperlidae stoneflies have a cylindrical banded abdomen. When observing their mouthparts, the glossa and paraglossa form a three-pronged (open) notch, and their hind wing pads are parallel (not divergent). Cerci have a vertical fringe of hairs pointing away from the abdomen. Setae on the pronotum are found primarily at the corners.

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: 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

ORDER: Trichoptera
FAMILY: Uenoidae
GENUS: Neophylax

Neophylax are a stouter trichoptera. The head is scrunched in between the arms and the anal hooks are connected directly to the bottom of the abdomen instead of to the prolegs. There are small ovals on the ventral abdominal segments. 

Because our samples were taken in summer, there were large numbers of Neophylax prepupae found.  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

Riffle beetles appear in the streams as adults and larvae. The larvae of Stenelmis have a sternum on the ventral side of the pronotum.

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 square in cross section and made of plant materials.

© Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Ephemeroptera
FAMILY: Ephemerellidae
GENUS: Ephemerella

Ephemerellidae mayflies have no gills on abdominal segment 2 and usually have dorsal abdominal spines. Mayflies in this genus have long intersegmental setae that extend laterally and well-developed maxillary palps.

ORDER: Plecoptera
FAMILY: Peltoperlidae
GENUS: Viehoperla

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. Stoneflies in the Viehoperla genus 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.