order
Coleoptera
“Adult Beetles”
Coleoptera
“Larval Beetles”
Diptera
“True Flies”
Ephemeroptera
“Mayflies”
Hemiptera
“True Bugs”
Lepidoptera
“Aquatic Caterpillars, Snout Moths”
Megaloptera
“Alderflies, Dobsonflies, and Fishflies”
Odonata
“Dragonflies and Damselflies”
Plecoptera
“Stoneflies”
Trichoptera
“Caddisflies”
family
Elmidae
Macronychus glabratus
“Riffle Beetle Larvae”
Genus Overview
Only 1 species in North America. Found on submerged wood. Range is mid central US to east coast.
Characteristics
POLLUTION TOLERANCE
Southeast: 4.7 and higher
Upper Midwest: 4 and higher
Midwest: 2.9 and higher
FEEDING HABITS
Collector / Gatherer
MOVEMENT
Clinger
DISTRIBUTION
Widespread (east of the Rocky Mtns.)
HABITAT
Lotic-depositional
Lotic-erosional
Lotic-erosional
Diagnostic Characters
Order
Eye Spots
Lateral Gills USUALLY Absent
USUALLY 4-5-Segmented Legs
Family
Brown, Sclerotized, Spindle-Shaped Body
Operculum
+ Expanded Character List
Order:
Larvae: Usually without lateral abdominal gills. If gills present, then 4 hooks clustered on segment 10. Thoracic legs each usually with 4 or 5 segments and with 1 or 2 claws; if without legs, head distinctly sclerotized and posterior body (thorax and abdomen) simple, without gills, hair brushes, suckers, or breathing tube. Eye spots usually present, but compound eyes absent.
Family:
Labrum and clypeus separated by distinct suture. Antennae 2–3 segmented. Head with ocelli in groups of 5. Legs adapted for walking, sometimes small, each 3–4 segmented and with single claw. Thoracic tergites clearly defined. Abdomen 9-segmented, ventral gills absent from segments 1–8. Segment 9 (posterior-most segment) with ventral lid-like flap (operculum) concealing thread-like gills and pair of hooks. Body strongly sclerotized (hardened), dark brown or red-brown, roughly cylindrical or spindle-shaped, with head and legs visible in dorsal view.
Genus:
This genus is without sclerotized posterior sternum plates behind the forelegs. The terminal segment ends extremely divided. There are only 6 abdominal pleura.
Dorsal
Ventral