I wasn't able to focus on this beetle but I think the violet sheen is clear.
No interactions present.
C. problematicus, I think, on pronotal shape and elytral sculpture.
C. problematicus is not shown in my book.
Insect guides like that by Chinery are great (assuming you're using something like this for the ID?), but unfortunately they don't always tell you that there is another very similar species to consider. I've been caught out by this many a time and have now learnt to take Chinery with a pinch of salt. I often use it as a starting point and then assume that there is some ridiculously similar beast that isn't in the book! Sometimes this is stated in the book, but you can never be too careful. Clearly, there are just too many species of beetle! Makes it more of a challenge at least, but sometimes a bit of a nightmare...
Moral - don't use Chinery for species ID - it don't work!
However, as Nature girl says, it is very useful for getting into the right area - such as family or even genus. Know Chinery's limitations and it can be your ally.
BMIG website: www.bmig.org.uk (centipedes, millipedes & woodlice)
BMIG Newsletters ~ www.bmig.org.uk/view/resource/bmig-newsletter
BMIG Bulletins ~ www.bmig.org.uk/view/resource/bmig-bulletin
Note the comments below, and for Carabus use http://www.record-lrc.co.uk/Downloads/GenusCarabusillustratedkey.pdf.
Also see useful hints and guides at http://markgtelfer.co.uk/beetles/carabidae-ground-beetles/
I dont know which book you have, I have 2 by Michael Chinery and I like them both, one has photos and the other top quality illustrations. The latter omits as many Carabus species as it includes in the illustrations anyway. It might include references to a couple in the text only. You would think it necessary to inc. problematicus alongside violaceus as they are so similar.
As Nature girl says a bit of checking is usually necessary even when you think youve found your species in Chinery, eg my illustrated book gives Carabus aurata, an introduced species to a small part of England which looks a lot like the widespread and native Carabus nitens which isnt illustrated. Good books but not comprehensive!
I have a copy of Chinery from 1986! Collins guide to Insects of Britain & Western Europe (don't tell anyone!). There are about 25,000 insects in UK, my copy of Chinery covers only 2000 - AND that includes European species that do not occur in Britain.
For Carabids (ground beetles) I use Luff 2007 - see http://www.field-studies-council.org/publications/pubs/the-carabidae-(ground-beetles)-of-britain-and-ireland.aspx This includes ALL 350 British species (known until 2007). Updates at http://markgtelfer.co.uk/beetles/carabidae-ground-beetles/ My 1986 Chinery lists 30 species (less than 10% of the British fauna) and two of those don't even occur in Britain.
Trouble is it is expensive to buy the all of latest ID books for all invert groups and that is why Chinery is very useful provided you are aware of, and work within, it's limitations.
All the best
Thanks for the link. This one isnt bad either but as its beetles of Ireland there will be some British species not included, eg Carabus violaceus. Still useful though. I'm sure youve already seen it.
I bought my Chinery books when I first started taking an interest in insects in 2007 and they were a joy to get hold of but truth be told I rarely use them now for IDing, sometimes to my detriment because you can get a nice surprise on occasion when you do open them and find a good illustration and accompanying info. of something you struggled to ID with websites. Limited but still nice to have and were really enjoyable when first purchased.
I do have a book by Chinery.
I shall bookmark those links and refer to them in future.
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