Yes they do. There are multiple sources confirming this, but for your grade schoolers, this one looks good to me: http://jeb.biologists.org/content/211/15/iii.full best regards, Christina *********************************************** 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