To start to differentiate the British Isles species of the subfamily, you need to look at the relationship of the intramedian cell (IMC) and the radio-medial crossvein (RMCV).
If the RMCV is exactly at the apex of the IMC or not reaching the cell (see below image), you will have the Chrysoperla carnea group of species or Peyerimhoffina gracilis (click link).
The crossvein RMCV coinciding with cell IMC (see below image) gives you the rest of the Chrysopinae species (click here).
