Identifying insects is often thought to be difficult, but a little practise will soon pay dividends, and most gardeners know more about insects than they realise. We must be able to put a name to an insect if we want to find out about its natural history, and whether it is likely to be a friend or foe in the garden. The trick is to keep things simple, and build up experience slowly. One place to start is by understanding how taxonomists classify insects, so that insect identification books become less daunting. (Taxonomy is the science of naming and classifying organisms in a way that reflects their natural relationships.) Taxonomists categorize organisms into separate groups (taxa; singular taxon), based on how they look and (increasingly) their DNA. Organisms within a given taxon have common features, and are thought to have evolved from a common ancestor. For example, the marmalade hoverfly can be classified under a number of different heading, depending on how exclusive we want to be. The figure below illustrates this.