University of Alberta Museums Search

Common NameBoreal water beetle SeasonalityAdult population peak in late spring, declining into fall (Aiken and Wilkinson 1985). IdentificationSmall to medium size (22.6 to 32.0 mm), elongate body (Larson et al. 2000). Brown-black to black - many with green appearance. Basal segments of antennae yellow, terminal segments darker. All pronotal margins bordered with yellow. Lateral border of elytra yellow, not reaching apex. Females with yellow striae and dark ridges. Yellow ventral surface, except brown-black metasternum, reddish metacoxa, margins of abdominal sterna narrowly black and thoracic sclerites with narrowly black margins. Dark basolateral marking on second and third sterna. Yellow or reddish legs.
Royal Alberta Museum page

SeasonalityAll teneral specimens from late July. IdentificationLarge (27.5 to 34.0 mm), elongate body (Larson et al. 2000). Brown to black - some with green appearance. Ring of yellow around inner margin of eye. All pronotal margins bordered with yellow. Lateral margin of elytra yellow and narrowing to apex. Yellow or reddish ventral surface, expect thoracic sclerites margins narrowly brown-black and metasternum medially and metacoxa dark red. Pale abdominal sterna, with basal margins of first through third sterna narrowly brown-black. Yellow or yellow-reddish legs, brown-black dorsal surface of tibia.

SeasonalityAdults emerge from March to October. IdentificationLarge (26.3 to 32.5 mm), elongate body (Larson et al. 2000). Brown-black to black - some with green appearance. Pronotal margins and elytra broadly yellow. Large medial chevron on head. Basal antennal segments yellow, terminal segments reddish. Most of ventral surface yellow, except darker and reddish abdominal sterna, metacoxa and medial metasternum. Elongate brown-black spot along posterior margin of metacoxa. Yellow legs with reddish tibia and tarsi.

SeasonalityAdults emerge from July to September. IdentificationLarge (29.7 to 40.0mm), broadly elongate (Larson et al. 2000). Black - some with green appearance. Basal antennal segments yellow, darker and reddish terminal segments. All pronotal margins bordered with yellow. Females with reddish or brown-black striae and black ridges. Reddish yellow or reddish ventral surface, except red metacoxa, medially brown-black metasternum, and black anterior and posterior margins of abdominal sterna. Brown-black or black sternal basolateral maculation - progressively smaller to posterior. Yellow or reddish legs.

SeasonalityFlight records from April to November, all teneral specimens collected in July. IdentificationSmall (22.0 to 27.9 mm), oval-shaped (Larson et al. 2000). Brown to brown-black - some with green appearance. Median chevron on head. Basal antennal segments yellow, terminal segments darker. Lateral and anterior margins of pronotum with yellow borders. Ventral surface yellow to reddish, except metacoxa yellow and metasternum brown-black medially. Yellow legs, with darker tarsi and tibia.

SeasonalityAdults emerge from July to September. IdentificationLarge (32.4 to 39.0mm), broad body (Larson et al. 2000). Dark brown to black - some with green appearance. Small chevron between eyes. Ventral surface of head yellow. Prosternum pale at lateral margins, brown-black medially. All margins of pronotum broadly yellow. Middle and hind legs brown-black with reddish basal portions, forelegs reddish anteriorly and brown-black posteriorly.

SeasonalityAdults emerge from July to September. IdentificationSmall (22.1 to 28.5 mm), oval-shaped (Larson et al. 2000). Brown to brown-black - some with green appearance. Median chevron on head. Basal antennal segments yellow, terminal segments darker. Lateral and anterior pronotal margins broadly yellow, basal margin narrowly yellow, expanded medial yellow border. Yellow to reddish ventral surface, except metacoxa yellow and metasternum medially brown-black. Apical and basal margins of abdominal sterna brown-black. Legs yellow with darker tarsi and tibia.

SeasonalityAdults emerge from July to September. IdentificationMedium size (24.2 to 28.1 mm), elongate body (Larson et al. 2000). Dark brown or black - some with green appearance. Small chevron between eyes. Basal antennal segments yellow, progressively darker toward tips. Pronotum with basal margin narrowly yellow or brown-black, anterior margin narrowly yellow and lateral margins broadly yellow. Yellow prosternum and prothorax, remainder of ventral surface dark red or brown-black. Forelegs yellow, femur of middle legs yellow to brown-black, hind legs brown-black.

Common NameGiant green water beetle SeasonalityAdults emerge from May to August. IdentificationMedium size (26.7 to 33.0 mm), elongate body (Larson et al. 2000). Reddish to black - some with metallic green appearance. All margins of pronotum and lateral margins of elytra broadly margined with yellow. Large medial chevron on head. Basal segments of antennae yellow, terminal segments reddish. All pronotal margins broadly yellow - basal margin narrow laterally and broadly expanded medially. Lateral margins of elytra yellow, narrowed and discontinuous at apex. Fore- and middle legs yellow to pale red.