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
Dytiscidae
“Predacious Diving Beetles”
Genus Overview
There are at least 106 species of this genus in North America. Adults and larvae inhabit both fast and slow streams and littoral zones of lentic habitats. They are piercing predators. Adults are climbers on rooted plants and efficient swimmers.
Characteristics
POLLUTION TOLERANCE
Mid-Atlantic: 8 and higher
FEEDING HABITS
Piercer / Predator
MOVEMENT
Diver
Swimmer
Swimmer
DISTRIBUTION
Widespread (east of the Rocky Mtns.)
HABITAT
Lentic-littoral
Lotic-depositional
Lotic-erosional
Lotic-depositional
Lotic-erosional
Diagnostic Characters
order
Elytra
family
Coxal Plate Not Wedge-like
Extended Hind Coxae
Large Spurs Absent
Scutellum Usually Visible
+ Expanded Character List
Order:
Adults with hardened forewings (elytra) covering the hind wings.
Family:
Ventrally, pronotum with conspicuous curved lines near each lateral margin (notopleural sutures). Metasternum without transverse sutures. Elytra covering entire abdomen or exposing only part of 1 tergite. Hind coxae each with median portion extending in posterior direction, dividing abdominal segment 1 into lateral sclerites, but not expanding into broad plates. Without large spur on end of each front tibia. Dyticidae without broad wedge-like hind coxal plate. Scutellum usually visible; if hidden, then front and middle tarsi apparently 4-segmented and hind tarsi each with 1 claw. Hind tarsi and usually tibiae flattened, streamlined, and bearing long, stiff swimming bristles. Body usually 3–25 mm long.
Genus:
Moderate-sized, 5 to 14 mm long, and black or brown, with elytra appearing leathery with small cracks or net-like. Pronotum margined. Males with tarsi of front legs swollen and bearing dense setae tipped with minute discs. Hind claws of equal length. Metacoxal lines not strongly convergent anterior of metacoxal lobes; elytra without longitudinal striae; metafemora with or without setae on posteroapical angles.
Dorsal
Ventral