UniPOSCA marker pen is popular in the UK 
http://www.thorne.co.uk/queen/marking.

Comes in five colours and has a bullet tip that gives a good round spot. 
Lasts well if applied properly (have 4 year old queens where the spot is 
still good).  I find that it is best to rotate it a little as I mark the 
queen so that the paint goes down onto the thorax, otherwise you can 
sometimes just paint the hairs which then wear away.

Best wishes

Peter
52.144442, -1.503509 

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html