Blue longhorned beetle

2016 November 9

Sam and Rosie caught this dark, metallic blue beetle for me on June 25, 2016.


This next picture includes my fingertip as a size reference. This is a fairly typical-size beetle, with a body about half an inch long.


The mandibles don’t look very predatory, and it has pretty long antennae.


The legs actually look long and muscular enough to be jumping legs, although it didn’t actually try to jump away from us.



I mean, just look at the size of those thighs![1]


This looks most like one of the several species of longhorned beetles in the genus Callidium. I’m not sure which one, though, and there is a good chance that this particular species isn’t up on BugGuide yet, since they say that there are 19 known species in North America, but only have pictures for 8. And, none of those eight species are shown as being in northern Michigan. One of the unpictured species has the name Callidium frigidum, which is the sort of name I would expect for an insect living in a frigid northern climate like ours, but unfortunately I obviously can’t compare mine against nonexistent pictures. I’ll have to post this one on the site to see what other people have to say about it.

Anyway, the beetles in this genus all seem to have larvae that are one sort of wood-borer or another.

[1] Well, femurs, actually. Since insects have exoskeletons, we are looking at the skeleton here, and the femur is the thighbone. Technically, its thighs are *inside*.

3 Responses
  1. November 9, 2016

    While bugguide doesn’t have a photo, Google Images shows results for Callidium frigidum similar to yours.

  2. November 11, 2016

    OK, out of that image search, these are Callidium frigidum. Unfortunately they are pinned and dried specimens, which tends to change the color and sometimes distort the body shape. They could be the same as my specimen, but mine looks bluer and a bit more slim and elongated. Which may or may not be because mine was still alive.

  3. Mark Sturtevant permalink
    November 23, 2016

    I would not rule out that this beetle is not YET known in northern Michigan, but yours may be the first described case of finding it up there, whatever it is. This does happen at times.

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