What's That Bug? does not endorse extermination

Big Black Beetle
As a young boy I was quite the bug collector: everything I ever caught I would study religiously until I knew the creature inside and out. At the tender age of 10, I considered myself an expert in the field of Centipedes and Earwigs. One insect I occasionally came across in my little bug hunting adventures as a kid was what I labeled the ”Big Black Beetle”. I become quite fascinated with the beetle and wanted to know more, but my search to find more answers about the bug proved to be unsuccessful. And as time went on I, unfortunately, stopped looking for bugs all together as other hobbies and interests beckoned, and the mystery of the ”Big Black Beetle” seemed to be forgotten. Then last week at work (I work at a log home construction site) I found it! I was lifting up some boards and spotted the little guy. Maybe you guys can help me solve this mystery once and for all!

Hi Braden,
We are fairly certain this is a Darkling Beetle, possibly in the genus Eleodes, but we want to check with Eric Eaton for substantiation and perhaps a species identification. A location would be a tremendous help. Eric wrote: ” LOOKS like an Eleodes, but not knowing where exactly it was collected, I won’t say for certain. Other genera of Tenebrionidae can look nearly identical. Eleodes are typical of true deserts. Coelocnemis and Iphtheminus (spelling?) tend to replace Eleodes at higher elevations, like in Ponderosa pine forest habitats.”

Thanks for your help guys! I live in British Columbia, Canada. For some reason I thought I included my location in my initial e-mail, sorry about that!

Update:  June 18, 2021
That probably is Coelocnemis californica in the photo. There is a great deal of mimicry between Coelocnemis and Eleodes, and in some areas they are quite difficult to tell apart from a distance. The surest way to differentiate Coelocnemis from Eleodes is to look at the ventral edge of the tibiae; Coelocnemis has a double row of golden setae which is completely absent from Eleodes.
C. californica is known from British Columbia and as far east as Montana. Its conceivable that it ranges further north and east, and its also possible that it has been spread by the human movement of firewood and other things as several other large tenebs have been.
Hope that helps you.
John Nelson


What's That Bug? does not endorse extermination
Location: British Columbia, Canada

5 Responses to Darkling Beetle: Coelocnemis californica

  1. tenebboy says:

    This is Coelocnemis californica … note the golden setae lining the tibiae.

  2. Beth Peart says:

    I’m curious because I live in Southern Ontario and as a kid I encountered large black stinky beetles like these when hunting sowbugs etc under rocks and fallen wood. All the demographics I can find on these say they should not be in Southern Ontario – but they sure were when I was a child. What stink beetle was I looking at?

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