Just checked my field guide. Apparently there are two species of ladybugs that are serious garden pests. Here's more info:

http://creatures.ifas.ufl.edu/veg/be...ean_beetle.htm
http://www.gaipm.org/top50/mexican.html
http://entweb.clemson.edu/cuentres/c.../veg/ce104.htm

McJulie