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 Cascades Brook |
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| Stream code: | OC_Cscds_640 |
| Basin: | Otter Creek |
| State or Province: | Vermont |
| Country: | USA |
| Latitude: | 44.152958 |
| Longitude: | -73.045921 |
| School: | Mill River Union High School |
The following are the most common invertebrates collected from this stream site.
Ceratopsyche
- 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. Biologists have gone back and forth between lumping this genus into
Hydropsyche and splitting it back out. ITIS currently lists it as a genus (Feb 2013) but we are aware of a recent paper that lumped it under
Hydropsyche.
Dolophilodes
- Order
- Trichoptera
- Family
- Philopotamidae
- Genus
- Dolophilodes
Baetis
- Order
- Ephemeroptera
- Family
- Baetidae
- Genus
- Baetis
- Common name
- The Little Olive
- Tied fly
- Sawyer Pheasant Tail Nymph
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.
Image of the long, dark wing pads.
Hydropsychidae
- Order
- Trichoptera (caddisfly)
- Family
- Hydropsychidae
- Common name
- net spinning caddisfly
- Tied fly
- Emergent Sparkle Pupa, Vermont Hare's Ear
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.
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.
Commonly found genera include Cheumatopsyche, Ceratopsyche, and Hydropsyche. Less commonly, we have found Arctopsyche and Potamyia.
Images of the forked trochantin and the paired sclerites.
Perlodidae
- Order
- Plecoptera
- Family
- Perlodidae
Stoneflies in the Perlodidae family do not have branching gills from leg bases. When observing their mouthparts, the glossae and paraglossae form a large three-pronged notch, or opening. The hind wing pads are divergent. Cerci, or "tails," are as long or longer than the abdomen.
Images of mouthparts, thehind wing pads and the ventral view.
Hexatoma
- Order
- Diptera
- Family
- Tipulidae
- Genus
- Hexatoma
This Tipulidae can be identified by the swollen 7th abdominal segment. The swelling is bulbous and frequently as much as 2X abdominal diameter in preserved specimens.
Rhyacophila
- Order
- Trichoptera
- Family
- Rhyacophilidae
- Genus
- Rhyacophila
- Common name
- Green Caddis
- Tied fly
- Henryville Special or Glass Bead Caddis
In our lab,
Rhyacophila is known as the "Michelin Man" due to its large banded body. It has a very obviously checker-patterned head. It also has terrifying anal claws with large accessory hooks.
Links to images that may be useful if you have a magnifying glass or microscope:
Checker-patterned head.
Anal claws with large accessory hooks.
Chironomidae
- Order
- Diptera
- Family
- Chironomidae
- Common name
- Nonbiting midge
- Tied fly
- Griffith's Gnat
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 caddisfly family Philopotamidae.
More information on Philopotamidae.
Agnetina
- Order
- Plecoptera
- Family
- Perlidae
- Genus
- Agnetina
Agnetina nymphs have cylindrical, striped abdomens. Like other Plecoptera, they have 2 tails and 2 claws on each tarsus. This genus has three black dots (ocelli) on the top of the head. Click to see the
three ocelli on the dorsum of the head (3 black dots at joint with the pronotum). This stonefly is characterized by the
filamentous gills located in the "armpits". Another important feature is the paraglossae and glossae extending different lengths. The
occiput has a transverse row of evenly spaced little hairs.
Agnetina has another row of evenly spaced hairs on the posterior edge of
abdominal segment 7.
Stenelmis
- 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.
Click here to see pictures of the sternum and
antennae-
Dicranota
- 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.
Image of the prolegs.
Gomphidae
- Order
- Odonata
- Family
- Gomphidae
- Common name
- clubtail dragonflies
Like other Odonata, members of this family have four wingpads. Like members of the sub-order Anisoptera, the abdomen terminates in five points. What distinguishes Gomphidae from Aeshnidae is the fact that Gomphidae has clubbed antennae.
Image of the four wingpads and the abdomen.
More information on Aeshnidae.
Cascades Brook
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