I did notice that too. Last year my wild grape vine had bunches of them, this year I looked and looked and never saw any. It is apparently the result of last summer's drought:
"Overall numbers of adults are likely to be lower this year due to last summer's drought. Eggs are laid by the adult females burrowing into the soil after mating. They tends to select areas of green grass and moist soil. Egg-laying apparently occurs primarily during the first two weeks of July in central Illinois, with first instar larvae hatching from them by early August. This timing is slightly earlier for southern Illinois and slightly later for northern Illinois.
The eggs take in water from the soil and expand after being laid. In dry soils, this does not occur completely, and many eggs do not hatch. In addition, the larvae (grubs) require eleven inches of rainfall or irrigation through the late summer into the fall to mature to the third larval instar and survive the winter."
I'm sure they are not gone permanently and this suggests their numbers will be rising again, since this July it was still pretty wet around here. It does suggest that if you want to reduce your JB population, don't water your lawn from say the beginning of August on. The lawn is where the grubs live. Of course it would help if you could convince your neighbors to quit watering their lawns too.