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For Insects, Spiders & Their Kin
For the United States & Canada
underwater beetle - Helophorus

underwater beetle - Helophorus
Ailsa Craig, Middlesex, Ontario, Canada
April 7, 2005
Size: 7-8 mm
The beetle seems coated with mud. I wonder whether it's the same kind as the one I saw last year about 10 minutes from here.

Images of this individual: tag all
underwater beetle - Helophorus underwater beetle - Helophorus

Helophorus grandis
With the size and the locality, it can only be Helophorus grandis, the biggest member of this genus in North America.

Thanks for checking, Pierre-Marc
However, I'm not very confident on the size estimate of 7-8 mm. It could be off by a couple of millimetres.

Also, there's 14 other species of Helophilus listed for Ontario in this PDF doc, and I'd like to have more info on them before calling this one grandis.

Based on Smetana (Review of t
Based on Smetana (Review of the Family Hydrophilidae of Canada and Alaska), the only other species bigger than 5 mm in Ontario is Helophorus oblongus that is between 4.2 and 6.3mm. The two species are easy to distinguish, but we need to see the elytral stries, what isn't the case on the pictures.

Very cool
Very cool beetle. You have got me wanting to look for these! Nice photo.


Stephen Cresswell
Buckhannon, WV