Rocky, Rocky, Rocky...
Ease off with the harsh chemicals my friend. You can do a much better job of grub control with milky spore and that won't whack your earthworms and other beneficials (they ain't all bad guys, Rock...). Plus milky spore is a livving organism that breeds where it has a food supply (grubs) so you only need to apply every five to ten years or so...cheaper to boot!
Four beetles (probably just black ground beetles, am I right?) is NOT worth poisoning the land you live on...
The new reformulation of Grubexx just got Scotts fined by New York State; seems they hadn't registered the new active ingredient (did you know about the new ingredient, Rocky?) Seems there are concerns about groundwater contamination and insufficient studies on the active ingredient, halofenizide. Cost Scott's $1,200,000, so New York State must think it's pretty bad, huh?
Just because they can sell it doesn't mean it's safe folks. And in this case they shouldn't even have been selling it!
Watch out for poisons they may kill someone you love, not just bugs...
Tell me you don't have well water, Rocky...