Insect Identification

Introduction to the Key

The key is adapted from Oldroyd (1958) and Chinery (1993), and provides a first step towards identifying an insect specimen. However, due to the range of variation within many insect Orders, it is impossible to cover all contingencies and the key will not track down unusual and difficult species. For these you will need to consult a reference book of entomology or scan through the listing and descriptions of insect Orders on this site.

Click here for a full list of Insect Orders

(classification of insects)

The key is in five parts: Parts 1 & 2 for insects with wings (adults) and Parts 3, 4 & 5 for those without wings (including adults and as far as possible immature stages). To use the key, you must always start at the beginning and work through each numbered step systematically. Each step of the key offers two alternatives ('a' and 'b'). Read these carefully and select the one that applies to your insect. Look at the number to the right of your selection. This gives you the number of your next step. Go to this number (simply click on your selection) and again select from the two alternatives. Follow this procedure with every step, until you reach a selection followed not by a number but by the name of the Order to which your insect probably belongs. Click on this name for more information about the Order and typical examples.

Click the icons for illustrated help on features described in the key. You can return to your place in the key by using the 'BACK' button on your web-browser or by clicking the step number below your selected illustration on the help page (it is a good idea to remember your current step number when following these links).

If you come to a step where neither alternative seems to fit your insect you may have gone wrong earlier in the key (retrace your steps and try again!), but more probably you are looking at an immature insect (i.e., a nymph or larva). Although broadly covered in the key, immature insects are often difficult to place without detailed microscopic examination and reference to very specialised terminology for their diagnostic features. The present key is too generalised for this purpose and immature stages are always likely to cause some difficulty (the larval stages of Endopterygota will probably cause the greatest problems in this respect, since many of them superficially resemble the adults of quite unrelated wingless insects). Good luck!

Click here for the main external features of Insects
and for the names of structures used in the Key

(structure of insects)

Click here for the Key

(identification key)