order
![](/images/illustrations/illustration_coleoptera_adult_v_160.png)
Coleoptera
“Adult Beetles”
![](/images/illustrations/illustration_coleoptera_larva_v_160.png)
Coleoptera
“Larval Beetles”
![](/images/illustrations/illustration_diptera_larva_v_160.png)
Diptera
“True Flies”
![](/images/illustrations/illustration_ephemeroptera_larva_v_160.png)
Ephemeroptera
“Mayflies”
![](/images/illustrations/illustration_hemiptera_adult_v_160.png)
Hemiptera
“True Bugs”
![](/images/illustrations/illustration_lepidoptera_larva_v_160.png)
Lepidoptera
“Aquatic Caterpillars, Snout Moths”
![](/images/illustrations/illustration_megaloptera_larva_v_160.png)
Megaloptera
“Alderflies, Dobsonflies, and Fishflies”
![](/images/illustrations/illustration_odonata_larva_v_160.png)
Odonata
“Dragonflies and Damselflies”
![](/images/illustrations/illustration_plecoptera_larva_v_160.png)
Plecoptera
“Stoneflies”
![](/images/illustrations/illustration_trichoptera_larva_v_160.png)
Trichoptera
“Caddisflies”
family
Elmidae
“Riffle Beetles”
Genus Overview
There are 33 species in North America. Adults are small around 2-4 mm in length. Adults lack tomentum on the foretibia.
Characteristics
POLLUTION TOLERANCE
Southeast: 5.4 and higher
Upper Midwest: 5 and higher
Midwest: 3 and higher
Mid-Atlantic: 5 and higher
0 = least tolerant, 10 = most tolerant
FEEDING HABITS
Collector / Gatherer
Scraper / Grazer
Scraper / Grazer
MOVEMENT
Clinger
DISTRIBUTION
Widespread (east of the Rocky Mtns.)
HABITAT
Lotic-erosional
Diagnostic Characters
order
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-120x120-2836-4836-1326-3326.jpg)
Elytra
family
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-120x120-3586-4340-740-1494.jpg)
5-Segmented Tarsi
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-120x120-4083-4524-583-1023.jpg)
Big Claws
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-120x120-3624-4416-728-1519.jpg)
Last Tarsal Segment
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-120x120-1253-2215-948-1910.jpg)
Thread-like Antennae
genus
![](https://static.macroinvertebrates.org/gigapans/197483/images.5e7a408b856a56473ad305f2fb6bdde1/197483-120x120-1817-3563-1354-3099.jpg)
Prosternal Process
![](https://static.macroinvertebrates.org/gigapans/197483/images.5e7a408b856a56473ad305f2fb6bdde1/197483-120x120-870-2051-713-1895.jpg)
Tomentum of tibia
+ Expanded Character List
Order:
Adults with hardened forewings (elytra) covering the hind wings.
Family:
Terminal segment of each antenna no longer than combined length of 2 preceding segments; antennae thread-like. Elytra concealing entire abdomen or exposing only part of 1 tergite. Each leg with 5 tarsal segments, last tarsal segment about as long as other segments combined and with big claws. Abdomen with 5 visible segments.
Genus:
Prosternum process narrower than head. Antennae filiform and 11 segmented. Elytra without an accessory stria. Tibia without tomentum. Hind coxae transverse and larger compared to fore- and mid- coxae.
![](https://static.macroinvertebrates.org/gigapans/197481/images.0a2f391d46e22449e8390c70d261061b/197481-357x240.jpg)
![](https://static.macroinvertebrates.org/gigapans/197483/images.5e7a408b856a56473ad305f2fb6bdde1/197483-361x240.jpg)
Dorsal
Ventral