Page 2 · Predaceous Diving Beetles (Dytiscidae) - 392 Species, Identification & Facts

Rhantus binotatus

Identification: Pronotum with 2 medial spots, part of lateral elytron margin dark brown to glossy black (from abdominal sternum 1 onward); black on head not extending anteriorly around front of eye.

Rhantus consimilis

Identification: Head pale anteriorly, posterior margin solid black, no frontal spots, pronotum with few or no black maculations, venter reddish yellow, no black markings

Rhantus gutticollis

Identification: Detail from this image : "Diagnostic characters include the pair of medial pronotal spots and the black colouration of the head narrowly encircling around the eyes (in the similar R. binotatus , the black colouration does not encircle

Rhantus suturalis

Length 10.5 to 12.5 mm. With a closer look at Rhantus suturalis the dense black punctuation of the elytra is visible; this punctuation on a golden yellow base gives the dark brown impression when seen from a normal distance. The beetle has a light ye

Rhantus wallisi

Identification: Pronotum with dark markings along both front and hind margins, markings on the hind margin at most narrowly extended to posterolateral pronotal angles; no central spots/markings on the disc

Sanfilippodytes compertus

Identification: Basal portion of elytra distinctly paler than apical portion; pronotum broadly red laterally, with disc black to dark brown; metacoxal plates coarsely and densely punctate .

Scarodytes halensis

Length 3.8 to 4.3 mm with lateral furrows on the pronotum and ladder-like first and second elytral stripes. This is the only species in this genus. The oval body, strong dorsal striped patterning (usually 5 stripes) and a dark underside are all usefu

Thermonectus basillaris

Identification: transverse line on the head, transverse narrow fascia of the thorax, and interrupted basal fascia of the elytra, yellowish. Det. M. A. Quinn, 2013 among the most commonly coll'ed beetles (at UV lights) at Laguna Atascosa NWR, Cameron

Thermonectus intermedius

Identification: Similar to, and variously treated as, T. basillaris ; and preliminary molecular data suggest they are the same species. Currently, T. basillaris is distinguished by the lack of the subbasal yellow band on elytra and genital structure.

Sunburst Diving Beetle

Thermonectus marmoratus

Ejects a milky fluid from its prothoracic defensive glands when disturbed, containing a mixture of steroid compounds, presumably as a deterrent to fish predators (Meinwald et al. 1998). The main steroid compound in the defensive secretion is a novel