Carabid larva

Yesterday I spent a short while spinning small boulders in search of beetles, mostly without any success whatsoever. Possibly the cold snap has driven them further underground, certainly I didn't find much. To be fair, I was mid WeBS Count so my attention was more on birds than beetles.

However, I did find this impressively large and distinctive beast

I recognised it as a larval carabid and, due to the large size, figured it must be something like a Carabus. A bit of online picture-matching led me to Pterostichus. The sheer size of the beast would lead me to think it may be Pterostichus niger, which certainly occurs here, but that's just guesswork. 

What I do know is that nowadays my camera seems incapable of taking sharp images. I've truly trashed the lens, it's scratched and the coating has come off. It's a mess (and less than 18 months old). If it's as simple as ordering a replacement lens and unscrewing the old one, I shall do that. If it's a case of the whole camera requiring nitrogen purging or some such then I'm going to have to think about a replacement. And looking after it properly! My Olympus TG-4 Tough has been discontinued, replaced by the TG-5 with its inferior macro stacking abilities. Arse, I do hope I can just order a replacement lens and fit it myself.  

Carabids of Earlish

I took a wander out of my square today, just a couple of miles up the road to Earlish to see friends. Earlish is quite a bleak, barren place dominated by damp moorland or sheep pastures. The name translates as "place of strife" though I've yet to see signs of trouble up there. Anyway, I came across these stones which looked as good a beetling spot as any!

And no, I didn't check beneath the big white one

Instant success! First stone turned held this brute of a beast beneath, well that's definitely not Nebria brevicollis! 

Coming in at a whacking 17mm, just check those gorgeous red femora! 

This guy went straight into a tube. I scooped three smaller, all black carabids into a pot and headed back down to Uig. 

Three of the four specimens keyed straight to Pterostichus. First up, the Big Boy himself. 

1) Hind angles of pronotum rounded, not toothed (yep) - 2

2) apical (claw-bearing) segments of tarsi with setae beneath (sure do) - 3

3) third elytral interval with a single dorsal puncture, length at least 14mm, femora reddish or black - Pterostichus madidus

The features mentioned:

17mm in length

This 'red-thighed' version is known as P.madidus f. concinnus. The typical form has black legs.

The two remaining Pterostichus both keyed through to Pterostichus nigrita, which I've seen before up here and indeed, is a common beetle in this part of the world. I did err towards P.adstrictus for a while, I really do have issues when it comes to understanding the descriptions/diagrams of fovea, but by using several sets of literature plus some online sites I came true in the end. Helpfully, I have one that I prepared earlier, complete with nads splayed out on the card alongside the body, so I know it's a good ID. 

The last specimen was a Nebria. And it wasn't brevicollis! The quality of this next image will doubtless blow you away...

HAHAHAHAHAHAHAHAHAHAHAAAA!!!!!!

Anyway, the important thing is that through the microscope it was readily apparent that these hind tarsal segments were glabrous with not a single stray pale hair in sight. Which goes an awful long way to nailing Nebria salina. Then I checked the elytral microsculpturing and compared it side by side with a specimen of Nebria brevicollis - it's actually really quite noticeably different! For a start it shows up quite clearly at a low magnification whereas you need to zoom right in to brevicollis before its microsculpturing becomes apparent. Generally, salina looks greyer and scratched as opposed to the blacker, more shiny surface of brevicollis at similar low power. Nice! I've only knowingly seen salina up Mount Snowdon some years back (wasn't the nivalis I was hoping for...)

(L-R) Pterostichus nigrita female, P.nigrita male, P.madidus male & Nebria salina female

I'm quietly happy that I have these correctly identified. This morning I found that I'd received a couple of comments regards yesterday's Amara specimen - the one I wasn't particularly satisfied that I had correctly IDed. Clearly I wasn't the only one having doubts! Anyway, in the light of day I noticed a hair sticking up on the right elytron, following this hair to its base revealed a scutellary pore to be present - hence completely rubbishing my ID of Amara aenea! 

Tonight I logged on to find that none other than Mark Telfer himself has rubbished the A.aenea ID. Good news - this means I can go back and try it again (and hopefully come up with the same species as Mark suggests!) Give me thirty mins and I'll go try it again...I just need to psych myself up a bit first.