Diatomaeous Earth....

Swimming pool supply store.

OR

http://ag-organics.com/Food-Grade-Diatomaceous-Earth-10-lb./M/B003QJBVH8.htm?traffic_src=froogle&utm_medium=CSE&utm_source=froogle

Sincerely,
Gargoyle

They have an exo-skeleton...The earth rubs off their waxy coating and the dry up