page 1
This beetle is described on the previous page. Above is a photo of the right side, also here the characteristic image of the Dytiscidae family: the flattened, streamlined shape, the hind legs fully transformed for swimming and the middle legs used for anchoring.
Below are two enlarged details of the tops of the middle and front legs. The left photo also shows, from top to bottom: the long antennae, then the shorter maxillary- and lip palps. (The antennae are bent slightly downwards in the photo, which makes the image somewhat confusing: it seems like the maxillary palps are above the antennae, but of course they are not, as you can see in the first picture on the previous page).
Below: on the left a photo of the underside of the beetle, on the right two enlarged sections of that photo, showing details of the front and middle legs with their adhesive discs.
The underside of the beetle is very dark. Unfortunately I did not take an extra, overexposed image, that would enable us to see the metasternal wings (see for example Agabus sturmii). In the photo above,the pointed spines (spurs) on the tibia of the right middle leg are clearly visible.These are typical of the Hydaticus species, as is a straight leading edge of the metasternal wings. (van Nieukerken, 1992). Both pictures show so the sucker discs (sucker setae).
Bibliography
See also the Bibliography of water beetles.
Nieukerken, E. van 1992, Dytiscidae - In M.B.P. Drost, H.P.J. Cuppen, E.J. van Nieukerken, A.M. Schreijer, (red.) 1992. De waterkevers van Nederland 154-156. - Uitgeverij K.N.N.V., Utrecht.
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