All MEB-1 records on one map

A Reference Locality (RL, plural RLs) is a geographical name contained in the Times Atlas of the World (preferably 9^th Comprehensive edition of 1994 or later) unequivocally referable to a certain place on an atlas map by means of geographical coordinates given in the gazetteer of the Atlas. One RL represents one or several sites of observation, capture or occurrence of a butterfly species situated in its vicinity and is represented on a distribution map by a dot or blend together with adjacent RL/RLs into a single dot. Because of the scale of the present maps one RL could cover an area of up to about 50 × 50 km but a higher density of RLs is advantageous, especially in areas of higher concentrations of butterflies and their sites. The Times Atlas of the World (9^th Comprehensive edition of 1994 or later) was selected because its gazetteer contains geographical coordinates, the maps are updated to show borders of new and resurrected European states (after the disintegration of the Communist block in 1989) and is generally the best geographical atlas available at present. The Times Atlas of the World is available in all major public and many private libraries, and thus enables full reproducibility of RLs. A simplified alphabetic index of about 8000 RLs was made available to recorders in the MEB handbook (KUDRNA 1996) and a final gazetteer containing 9145 preselected RLs with their geographical coordinates appears in a separate chapter of this book.

Plebejus argyrognomon (D, Rhoen)	Polyommatus coridon (D, Regensburg)

For the communication of data by recorders, two sizes of standard Recording Sheets (RS, plural RSs) were devised and guidelines published (KUDRNA 1996). The standard RSs proved satisfactory as long as recorders followed the instructions provided and filled them in legibly. Special internal RSs were devised in cooperation with the recorder concerned for the transfer of extensive data banks (e.g. converted national data banks) and formatted as necessary from case to case. These special RSs have proved most successful, saved much time and prevented many errors. A few recorders insisted on a direct input of digital data. From sheer necessity and as a test case, two sets of such data banks were converted and imported by K. LUX. Both files proved to contain many errors, the correcting of which has probably taken up more time than the input of the data banks from RSs would have taken. In principle, it is impossible to check such data sets thoroughly.