Chrysoperla carnea

One of our commonest green lacewings and perhaps the most widely observed due to its habit of entering houses in order to hibernate. It is, however, not the most straightforward to identify, and there are a couple of new species that could be overlooked as this if using Plant (1997) as your reference. My records suggest that this species has two generations, a summer generation peaking in July/August and an autumn generation peaking in September/October before hibernating and flying again in the spring.

There are three Chrysoperla species in the UK and these can be told apart from nearly all the other green lacewings by a small detail of wing-venation which is possible to see using a hand lens, and sometimes even in good quality photos. Each wing normally contains a small triangular cell (called cell IMC, arrowed in blue in the photo below) in the middle and towards the base. I occasionally see carnea with this cell missing in one wing, but present in the other, so you may need to check both wings (always a wise idea with lacewings anyway). Roughly opposite the tip of IMC there should be a small cross vein heading towards the leading edge of the wing (called vein RMCV, arrowed in red in the photo below), and the position of this vein is key. If it starts from the side of IMC, i.e. proximal (head-side) to the apex of cell IMC, then it's probably not Chrysoperla, but if it starts beyond or level with the tip of IMC then it's probably Chrysoperla (but could be Peyerimhoffina gracilis which hasn't yet been found in Norfolk - see here for details). Beware abnormal individuals - there's a carnea that didn't conform to this further down this page and I once found a Cunctochrysa albolineata which had no cell IMC in one wing and on the other wing a reduced cell IMC, the apex of which fell well short of vein RMCV - if I had not checked its abdomen I would have thought it was one of the Chrysoperla.

male Chrysoperla carnea, North Elmham (Norfolk, UK), 20th October 2021

Once you've got to Chrysoperla sp., lucasina is the first one to rule out. This has slightly more pointed wings with straighter tornus. It may have brown on the membrane on the side of the base of the abdomen, but I find that very hard to observe on many lacewings and it isn't present on every lucasina (don't confuse this with brown at the edges of the upper segments - you need to be looking at the membrane between the upper and lower segments). Unlike carnea, it doesn't turn brown in winter. It also has shorter hairs on the leading edge of the wings.

Chrysoperla pallida is not covered in Plant (1997) as it has been described more recently and females are not possible to separate from carnea. To sex them, if you look at a female abdomen from below you will normally see an opening (at least a groove) running centrally through two sections at the tip, whereas from the side males have a small lobe protruding at the tip of the abdomen (the 'lip' above the 'chin' - see annotated photo below). The relative size of the males' lip and chin are key to separating pallida from carnea - on pallida the lip is small compared to the chin whereas on carnea it is larger. Chrysoperla carnea also tends to have numerous dark hairs on the tip of the abdomen whereas these are normally all pale on pallida, however this difference is not consistent and reliable. What probably is more reliable is the length of hairs on the lip itself - these are long (dark or not) on carnea but much shorter on pallida (pale). Chrsyoperla carnea is very much more commmon in Norfolk than pallida.

When submitting records of Chrysoperla carnea, please do not use Chrysoperla carnea sensu stricto as this is ambiguous - recorders who are/were not aware of the new species pallida have used this term merely to indicate that they have ruled out lucasina (which was also lumped with carnea once). Equally Chrysoperla carnea agg. (or group) is ambiguous as it could mean Chrsyoperla carnea/pallida or Chrysoperla carnea/pallida/lucasina. I am happy to receive records of aggregates but to avoid doubt, please indicate precisely what you mean (in the notes if necessary - I'm aware that some systems don't currently give you useful options to select from). If you are claiming either carnea or pallida please indicate that it was a male, and if you find pallida in Norfolk please retain the specimen or at least take good quality photos of the abdomen tip in side profile.

Here on the close up of the tip of the abdomen you can see the relatively large lip compared to the chin. Also note the long hairs on the lip.

male Chrysoperla carnea, Wendling Beck Environment Project (Norfolk, UK), 25th September 2021

It's not usually necessary, but sometimes it can be easier to see the abdomen shape if you clear it in potassium hydroxide first. This is especially so if you're looking at a dried-up dead specimen.

male Chrysoperla carnea, Wendling Beck Environment Project (Norfolk, UK), 24th June 2022

Acquired wisdom is that female pallida cannot be separated from female carnea, so all females should be aggregated (although I don't know if pallida ever shows as many dark hairs on the abdomen tip as this one). Compare the structure of the abdomen tip to the males above for sexing.

female Chrysoperla carnea or Chrysoperla pallida, St Mary's Chapel, North Elmham (Norfolk, UK), 15th April 2022

Only Chrysoperla carnea and Chrysoperla pallida turn brown in winter so if you find a 'green' lacewing looking brown then you know it's one of these two species (assuming it isn't deep brown like Notochrysa capitata, but that looks quite unmistakeable and wouldn't be around in winter when the carnea and pallida are brown).

male Chrysoperla carnea, Honeypot Wood (Norfolk, UK), 30th March 2017

male Chrysoperla carnea, North Elmham (Norfolk, UK), 11th November 2021

The hairs along the costa (leading edge) of the wings are longer in carnea than lucasina. Based on a small munber that I've measured they are mostly over 0.18mm (180μm) and sometimes over 0.20mm (200μm) on carnea. They were just a little over 0.16mm (160μm) on a lucasina I measured recently. I take the measurements from around the middle of the costa.

male Chrysoperla carnea, North Elmham (Norfolk, UK), 9th November 2023

The pale yellow stripe along the dorsal side of the thorax and abdomen is, I think, always present on all three of our Chrysoperla species (at least I don't recall seeing one lacking it). However some of the other green lacewings share this character, so it is not sufficient to point to this genus. But a lack of a yellow stripe can sometimes be a helpful way to rule out Chrysoperla.

male Chrysoperla carnea, Wendling Beck Environment Project (Norfolk, UK), 11th August 2023

When looking for the brown membrane between the basal abdominal tergites and sternites (upper and lower segments) that is sometimes present on lucasina, don't confuse the membrane with the dark sides of the tergites. Here the membrane itslef is clearly green, but there is brown immediately above this on the sides of the tergites. Note that on some individuals the sides of the tergites appear to touch the sides of the sternites so that there is no membrane between them visible.

male Chrysoperla carnea, North Elmham (Norfolk, UK), 21st July 2023

You can see the membrane more clearly here (though this one is a female so I cannot exclude Chrysoperla pallida).

female Chrysoperla carnea or Chrysoperla pallida, North Elmham (Norfolk, UK), 15th July 2023

male Chrysoperla carnea, North Elmham (Norfolk, UK), 9th November 2023

I'm usually pretty wary of identifying lacewing larvae as there are no comprehensive references available to support doing so. There are a couple of references from the 1920s but these don't cover every species. I've not tended to be very successful in rearing them through to adults, but I did manage this one which must have been ready to pupate when I collected it. I missed the adult emerging from its pupal coccoon and it had already died by the time I noticed it had done so, in December. Unfortunately it was a female so I still can't be 100% sure if it was this species (very likely) or Chrysoperla pallida (much less likely).

female Chrysoperla carnea/pallida larva and vacated pupal coccoon, North Elmham Cathedral Meadows (Norfolk, UK), 20th June and 7th December 2020

One female I caught laid eggs in the pot. Lacewing eggs (at least some species - not sure if this is true for all or not) are laid individually on long stalks as can be seen here (I couldn't get both the egg and the base of the stalk in focus at the same time, and my Photoshop skills aren't up to merging the images). The eggs started off green but turned white.

egg laid by female Chrysoperla carnea/pallida, North Elmham (Norfolk, UK), 18th May 2022

The eggs hatched a few days later. Three of the early instar larvae are shown below including one still on its egg. Sadly I wasn't able to grow them out to pupate let alone emerge as adults.

Chrysoperla carnea/pallida larvae, North Elmham (Norfolk, UK), 30th May 2022, emerged from eggs laid on 18th May

Here's the offspring of another one that laid eggs in the pot.

Chrysoperla carnea/pallida larva, Wendling Beck Environment Project (Norfolk, UK), 22nd July 2023, emerged from eggs laid by female caught on 12th July 2023

On this example the venation was aberrant on both wings, vein RMCV being clearly (if only slightly) proximal to the tip of cell IMC on both forewings. A combination of other characters (entirely green veins, pale thoracic stripe, long costal hairs at an angle, palps unmarked on inner side, etc.) confirmed that it was Chrysoperla.

female Chrysoperla carnea/pallida showing forewings, North Elmham (Norfolk, UK), 13th August 2023

Both antennae on this individual had darkened segments on the antennae, so perhaps recalling those species (e.g. Chrysopa commmata) that have black second segments of their antennae. However the markings were asymmetric, on different segments on the two antennae (and not the second segment on either side) and they were browner and (especially on one side) not as clear-cut as on commmata. Of course the wing-venation also helped confirm that we were dealing with a dirty Chrysoperla and not Chrysopa.

male Chrysoperla carnea showing antennae, wings, close-ups of bases of both forewings and abdomen tip from side, North Elmham (Norfolk, UK), 16th July 2022

The forewings of this one seemed to have a very slight point at the apex which made me look twice. But they aren't as pointed as lucasina, and the edges round from the apex are too evenly rounded. I'm yet to identify any differences in the internal structures of the abdomen between the three species of Chrysoperla, but that's not to say there aren't any - I haven't examined many lucasina or pallida.

male Chrysoperla carnea, North Elmham (Norfolk, UK), 10th October 2023

Interested to find out whether there might be any differences in the internal structures of the genitalia I set about photographing these on a few specimens of carnea. There are two bits that are easily isolated and extracted from the abdomen, but I'm not sure what they are (I'm guessing one may be the aedeagus or penis). Note these were photographed in liquid not set on a microscope slide, so they aren't always laying perfectly flat - this is the reason for the apparent variation in length of the cemtral portion - where this is shorter it was tilted. In all of the following set of photos the live insect is shown before the close-ups of wings/abdomen or genitalic structures. On a couple I've included a photo of the side of the base of the abdomen - note the dark areas are on the sides of the upper segments (tergites) not (as may be the case in lucasina) on the membrane between the upper and lower segments.

9x male Chrysoperla carnea, North Elmham (Norfolk, UK), 10th October 2023

male Chrysoperla carnea, North Elmham (Norfolk, UK), 16th July 2023

It was recently suggested that the presence of narrow dark bar in front of the eye could be a useful feature for Chrysoperla pallida. This prompted me to investigate and photograph this area on a series of Chrysoperla carnea I had waiting to be examined. There is a dark bar present on most of these (all to some extent, but on a minority it was very indistinct), so if it is a useful feature for pallida it's not merely the presence of it that matters. Maybe there is a difference in its breadth or shape, but if so I think this needs defining precisely, and given the variation in carnea I suspect it won't be a foolproof character. In the photos below the whole live insect photos are shown before the close-ups of the face (and in once case abdomen).

21x male Chrysoperla carnea, North Elmham (Norfolk, UK), 16th July 2023

male Chrysoperla carnea, North Elmham (Norfolk, UK), 24th June 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 26th June 2022

2x male Chrysoperla carnea showing wings and abdomen of first, North Elmham (Norfolk, UK), 5th November 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 17th July 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 23rd October 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 29th June 2022

2x male Chrysoperla carnea, North Elmham (Norfolk, UK), 24th June 2020

male Chrysoperla carnea, North Elmham railway (Norfolk, UK), 12th September 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 14th April 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 2nd October 2021

male Chrysoperla carnea, Wendling Beck Environment Project (Norfolk, UK), 13th August 2021

male Chrysoperla carnea, St Mary's churchyard, North Elmham (Norfolk, UK), 25th July 2021

male Chrysoperla carnea, North Elmham Cathedral Meadows (Norfolk, UK), 21st May 2019

male Chrysoperla carnea, North Elmham Cathedral Meadows (Norfolk, UK), 23rd June 2020

male Chrysoperla carnea, North Elmham (Norfolk, UK), 7th April 2018

male Chrysoperla carnea, Whitwell Street (Norfolk, UK), 3rd September 2020

male Chrysoperla carnea, North Elmham (Norfolk, UK), 28th September 2021

male Chrysoperla carnea, Elmham Park (Norfolk, UK), 15th August 2923

male Chrysoperla carnea, North Elmham (Norfolk, UK), 30th June 2022

male Chrysoperla carnea, North Elmham Cathedral Meaodws (Norfolk, UK), 9th May 2021

male Chrysoperla carnea, North Elmham (Norfolk, UK), 29th October 2022

male Chrysoperla carnea, High Hurstwood (Sussex, UK), 23rd July 2022

male Chrysoperla carnea, North Elmham (Norfolk, UK), 8th May 2021

male Chrysoperla carnea, North Elmham railway (Norfolk, UK), 31st August 2022

male Chrysoperla carnea showing forewing and tip of abdomen (in life and after clearing), North Elmham (Norfolk, UK), 15th March 2022

male Chrysoperla carnea, Wendling Beck Environment Project (Norfolk, UK), 13th July 2023