I'm using K9 Advantix, which is for fleas, ticks and mosquitoes--I wanted something with mosquito control since we live near a lot of wetlands. It's applied just like Frontline, except I'm supposed to apply it in four "dots" on Lefty's back (maybe it's because he's a bigger dog; I don't know). It's easy to apply but a bit greasy. He hasn't demonstrated any desire to lick it off, however. It's been working fairly well, I think, though I have seen him nibbling at his tail once or twice since warm weather arrived.

This is a more expensive product, but since the mosquitoes are so bad here, I was willing to pay extra for more protection. It's available at drugstore.com, but I purchased mine through my vet and got one vial free.