Butterflies and moths: demonstration of an interactive key


M. J. Dallwitz, T. A. Paine, and E. J. Zurcher

How to use the key

To identify a ‘specimen’:

1.  Press the Restart button (Restart identification).

2.  The top-left pane shows a list of characters. Normally, the pane is headed ‘Best Characters’ and the best characters are at the top; if not, you can restore this setting by pressing the Best order button (Best order). Click on a character.

Intkey window at start of identification

3.  The program displays an illustration to help you interpret the character. There will be boxes describing the character ‘states’, or a box for entering values such as lengths. Some characters have explanatory notes, which may be viewed by pressing the ‘Notes’ button. Click on the state, or enter the value, that applies to your specimen, and press ‘OK’.

Intkey state-selection window

If you are not sure, do not guess a single state or value. Instead, click on more than one state, enter a range of values, or press ‘Cancel’ and try another character. To deselect a previously selected state, click on it again.

4.  The ‘Taxa Remaining’ (top-right) pane shows the taxa that match the information that you have entered. The ‘Taxa Eliminated’ (bottom-right) pane shows the taxa that do not match, with the number of mismatches in parentheses.

Intkey window after using 1 character

5.  Repeat from step 2 until ‘Identification complete’ or some other message is displayed in the top-left pane. A ‘Help’ button is also displayed. You can press this to obtain information on how to proceed (for example, how to check the result).

Intkey window at end of identification

If, at any stage, you think you have made a mistake and want to correct it, click on the appropriate character in the ‘Used Characters’ (bottom-left) pane. The program displays the character illustration again, and you can change the information that you previously entered. You can remove the character from the identification by clearing all the information.

Checking the result

You should check your identification against the information that can be obtained by pressing the Information button (Information about taxa). The information usually includes full and diagnostic descriptions. A diagnostic description aims to distinguish the taxon from all the others, using only characters that have not already been used in the identification. You can also display the illustration of the remaining taxon.

If the descriptions or illustration are inconsistent with the tentative identification, you can increase the ‘error tolerance’, by means of the Information button in the ‘Characters’ toolbar (in the top-left pane). This allows a greater number of mismatches before taxa are eliminated, so some taxa that were previously in the ‘Eliminated Taxa’ pane move to the ‘Remaining Taxa’ pane. The identification process can then be continued exactly as before, until only a single taxon remains. You can then find your mistake by pressing the button labeled ‘Differences between the specimen and the remaining taxa’.

To familiarize yourself with this process, try making a deliberate error, and then recovering from it. Here is an example, using the ‘specimen’ shown below.

Specimen to be identified

Select ‘antennae feathery along the whole length’ instead of the correct value (‘antennae smooth, and thicker at the tip’). Proceed with the identification, and arrive at the following result.

Intkey window with a deliberate error

The descriptions and illustration available via the ‘Information’ button show that the result is wrong. Press the Set tolerance button (Set error tolerance), and set the tolerance to 1. This brings back into contention all taxa that differ in only one respect from the description of the specimen, as shown below.

Intkey window after setting tolerance to 1

Then proceed with the identification as before, and arrive at the following result.

Intkey window at end of identification with tolerance 1

This time, the information you can obtain via the Information button button shows that the answer is right. To find the original error, press the 'Differences from the specimen' button button (Differences between the specimen and the remaining taxa), which displays the following window.

Intkey window showing differences from the specimen