This, I believe, is a carpenter bee (Xylocopa spp.), and I caught it collecting nectar from some salvia I have growing in my front yard (Salvia guaranitica ‘Black & Blue’). It appears to be doing exactly what I find described by Steve Buchman of The Bee Works:
From time to time carpenter bees are quite ingenious in their foraging for nectar. On flowers such as salvias, penstemons, and other long, tubular flowers the carpenter bee, due to its large size, is unable to enter the flower opening. Instead they become nectar robbers. Using their mouthparts they cut a slit at the base of corolla and steal away with the nectar without having pollinated the flower.