I'm sorry I did not see this post until just now... I am an entomologist who occasionally deals with odd infestations. I have never dealt with these beetles, though I am familiar with them. Of course, most integrated pest management systems suggest removing them by hand (carefully, wearing gloves), which can be very difficult if there are large numbers. If it is in an area where the soil is not too exposed, you might have good luck with some sort of small vacuum cleaner, like a dust buster. be sure to wear a dust mask, because the cantharadins may be aerosolized by the moving air. I have had very good success with this at times with other aggregating insects. Let us know how it turns out, and best of luck.
