Matrix key Guide

How to start an identification

Most users will have obtained the specimens directly from a given host plant. In that case the first step should be a host plant search using the Host plants module. Behavioral characters and feeding habits will offer further clues for identification.


Although in most cases the comparison of descriptions and pictures of the species known from a given host, often provide good data for species identification, in certain cases the use of the IdentifyIt module might be necessary. In such case the recommendations summarized below should be followed.



As already stated, not all characters are equally trustworthy and powerful, especially at the very beginning of the identification. Therefore I selected a series of particularly useful characters, which should always be checked in agromyzid specimen. These characters should be known to any experienced agromyzid worker for they do both, ease identification and make it more reliable.


In order to find the above mentioned characters press the button "sort.." and check, if the order of the characters is set on "entry order" and "ascending". Subsequently, you will find at the top of the character list 13 major external characters. After having opened IdentifyIt for the first time save this order as the default setting.

Beneath the 13 most powerful adult morphological characters, you will find some biological characters (prefix "bio") and some larval characters (prefix "imm"). These characters are also very useful, but they require information on host plants and immature stages.


For example you will find a character where you can decide whether or not the species feeds on grasses.

For the taxa the sort order "Match percentage" and "descending" should be preferred. That means, those taxa are displayed on the top, which have been best described by the search pattern previously entered.


After having dealt with the particularly important characters, the sort order of the characters should be changed to "Separation coefficient" (again by pressing the "Sort.." button). Subsequently, some particularly powerful characters will be selected to separate the remaining taxa (objects) supported by the current search pattern. However, the experience shows that the separation coefficient not always finds the most informative characters for agromyzid identification.


After going through the data matrix, the host plant of the identified species should be found in the host plant module. The host plant-species or genus can also be of great help for identification, but note that there are some very polyphagous species (Bionomics) and there might be species with incompletely known host range.


It will often happen that the identification procedure will not result in a single species for the reasons discussed above. But even in those cases, where an unambiguous result was achieved, some more information and pictures on the male genitalia available in the species module should be compared. For a guide to dissection techniques see the section Dissection of male genitalia.