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big jawed water bug - Dytiscus

big jawed water bug - Dytiscus
Worcester, Worcester County, Massachusetts, USA
April 28, 2006
Size: 12mm
Found in a beaverpond swamp.

Moved from Dytiscus.

Moved from Rhantus.

Dytiscus larva
This is a first-instar larva of the genus Dytiscus. Its characters are urogomphi and last abdominal segment with natatory setae and V-shape of anterior margin of the prementum (it is possible to see through the transparent head). No doubt - Dytiscus larva.

Moved from Dytiscus.

Thanks Tim

Dytiscus sp.
probably an early instar

After reviewing my id again, this appears to be a larva of a Rhantus sp...for some reason I didn't notice the lack of setae on the 7th abdominal segment. sorry!

Predacious Diving Beetles

Very nice photos. Both would appear to be aquatic beetle larvae of family Dytiscidae, Predacious Diving Beetles, perhaps Cybister or some closely related genus.

Water beetle larvae at last! Neat finds, Tom. Now, when this pupates, a female bomba*dier beetle will try to hunt it down and lay an egg or two on it so her larvae can burrow in and feast their way to maturity. I wonder if their are other things that parasitize water beetle larvae.

Aquatic Coleoptera Parasites

Some aquatic Hymenoptera (Wasps) parasitize aquatic Coleoptera. This can be extensively viewed in Table 19A, on pages 482-483 of Aquatic Insects of North America (Third Edition), in the chapter on Aquatic Hymenoptera written by Kenneth S. Hagen, edited by Merritt/Cummins.

Predacious Diving Beetle Larva
Now I can see why they're called "predacious" with those jaws. Thanks Roger and Jim for the info.

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