Difficulty
An attempt to convey the ease or difficulty of identification. This is necessarily subjective and depends largely upon your previous experience.
| 1 | Easy to moderate. No more difficult than most hoverflies. Good keys available. |
| 2 | Good families to move on to for those with experience of group 1. Only a small proportion of difficult species and genera. If genital characters are needed, they are easily seen providing the genitalia are hinged out (e.g. hoverfly genus Sphaerophoria). Keys available, but they may be older and require supplementing with other, more recent, literature. |
| 3 | Can be tackled successfully given care and experience, but are quite taxing. Normally require access to a microscope and accurate species identification often requires genitalia preparation. Keys may not be available or are out of date, so access to a range of supplementary literature is necessary. |
| 4 | Require considerable experience and a good microscope. Microscopic preparations of genitalia, and perhaps other features, are essential. Access to voucher collections and a good library also necessary. |
| 5 | Impossible for all practical purposes due to taxonomic difficulties and/or lack of recent keys. |
