Cucumbers and Cucumber Beetles

I see these little yellow and black striped bugs every day on my cucumbers and I just squish them.  Some of them are too quick for me and fly away:

The Organic Gardener's Handbook of Natural Insect and Disease Control says to use a pyrethrin spray or dust on both sides of the leaves - especially the new leaves - to get rid of them.  I did this, but I still continue to see them.  Not too many of them (yet), and thankfully, I planted a lot of cucumbers.  They seem to be doing well.