Empicoris culiciformis, near Carlisle, 10 June 19 (3 of 5)
Empicoris culiciformis Assassin Bug found on a concrete fencepost by the River Petteril under the M6 motorway bridge near Carlisle, 10 June 19.
To say the least, this was a lucky find! I'd originally intended visiting Glasson Moss today, but despite having checked the CCC's roadwork map before setting out, the Burgh road turned out to be closed yet again. So, in a fit of pique, rather than finding a workaround I turned tail and headed for the Wreay Woods area instead. It was then that I fortuitously spotted this small and slender insect in near-darkness as I was heading through the M6 underpass (as shown in Photo 1, taken later in the day)!
I was pretty sure at the time that it was an Empicoris vagabundus, as it's the only Assassin Bug that I've ever seen in Cumbria, and in fact I'd found one just a few hundred metres away at the edge of Newbiggin Wood on 18/10/18. However, this option was soon dismissed on getting home as it was measured at 4.3mm in length, ie well outside of the 6-7mm range specified on the British Bugs website for this insect. The only other "Thread-legged Bugs" found in the UK are Empicoris culiciformis and E. baerensprungi, both of which are in the size range 4.1 - 5.5mm. According to NBN Atlas, the former is more widespread nationally, with several records in the Carlisle area, whereas the latter is relatively scarce and apparently confined to the south of the country.
Photos 2 - 5 were all taken using the integral camera on my SX10D microscope: Photos 2 and 3 give dorsal views of the live insect; Photo 4 shows the side of the abdomen (one set of wings removed) and one of the forewings; and Photo 5 gives a lateral view of the front of the insect, showing the upper profile of the pronotum (middle legs removed).
Note on identification: The following link refers to a key by Peter Kirby which apparently states that E. baerensprungi has a tubercle on the mid-line of the rear margin of the pronotum, which is absent in the case of E. culiciformis:
diptera.info/forum/viewthread.php?thread_id=9128
Also, a sketch of this feature can be found on the following website by searching for "Empicoris baerensprungi", where it's described (English translation of the Russian original) as being a "high conical tubercle":
macroid.ru/determination.php?cat=594
It can be seen from Photo 5 that although there's a small protuberance on the relevant part of the pronotum - indicated by an arrow - it certainly does not constitute a "high conical tubercle", and therefore the bug can only be Empicoris culiciformis.
Empicoris culiciformis, near Carlisle, 10 June 19 (3 of 5)
Empicoris culiciformis Assassin Bug found on a concrete fencepost by the River Petteril under the M6 motorway bridge near Carlisle, 10 June 19.
To say the least, this was a lucky find! I'd originally intended visiting Glasson Moss today, but despite having checked the CCC's roadwork map before setting out, the Burgh road turned out to be closed yet again. So, in a fit of pique, rather than finding a workaround I turned tail and headed for the Wreay Woods area instead. It was then that I fortuitously spotted this small and slender insect in near-darkness as I was heading through the M6 underpass (as shown in Photo 1, taken later in the day)!
I was pretty sure at the time that it was an Empicoris vagabundus, as it's the only Assassin Bug that I've ever seen in Cumbria, and in fact I'd found one just a few hundred metres away at the edge of Newbiggin Wood on 18/10/18. However, this option was soon dismissed on getting home as it was measured at 4.3mm in length, ie well outside of the 6-7mm range specified on the British Bugs website for this insect. The only other "Thread-legged Bugs" found in the UK are Empicoris culiciformis and E. baerensprungi, both of which are in the size range 4.1 - 5.5mm. According to NBN Atlas, the former is more widespread nationally, with several records in the Carlisle area, whereas the latter is relatively scarce and apparently confined to the south of the country.
Photos 2 - 5 were all taken using the integral camera on my SX10D microscope: Photos 2 and 3 give dorsal views of the live insect; Photo 4 shows the side of the abdomen (one set of wings removed) and one of the forewings; and Photo 5 gives a lateral view of the front of the insect, showing the upper profile of the pronotum (middle legs removed).
Note on identification: The following link refers to a key by Peter Kirby which apparently states that E. baerensprungi has a tubercle on the mid-line of the rear margin of the pronotum, which is absent in the case of E. culiciformis:
diptera.info/forum/viewthread.php?thread_id=9128
Also, a sketch of this feature can be found on the following website by searching for "Empicoris baerensprungi", where it's described (English translation of the Russian original) as being a "high conical tubercle":
macroid.ru/determination.php?cat=594
It can be seen from Photo 5 that although there's a small protuberance on the relevant part of the pronotum - indicated by an arrow - it certainly does not constitute a "high conical tubercle", and therefore the bug can only be Empicoris culiciformis.