About sawflies

Sawflies are insects from the huge order Hymenoptera, which includes the far better known wasps, bees and ants (as well as the even less well known parasitic wasps). They are usually grouped in the taxonomic suborder Symphyta, although it appears that this is at best a convenient grouping and the sawflies are not a monophyletic group (i.e. they don't all have a common ancestor that differs from the common ancestor of the other Hymenoptera). To a beginner they should mostly be readily recognised as a "fly or wasp"; if in doubt here, a close view will show they have two pairs of wings (not one pair as do flies). To recognise that a Hymenopteran insect is a sawfly, the easiest feature is the lack of a constricted 'wasp waist' that most other groups clearly show (although the constricted waist can be hidden in very hairy bees, and is not always obvious with some of the parasitic species).

There are currently about 600 species of sawflies recognised from Britain and Ireland. Although these are split into 9 families, about 500 of them are in just one of these, the family Tenthredinidae. Hence a good start is to determine the family. A key will be included on this site in due course, but after a while, the general appearance of the species in the different families can be quite distinctive anyway.