Fly lips are called labellum and fly feet are called tarsi. Both the labellum and tarsi contain taste receptors which help the fly find food. Think about that the next time a fly lands on your donut! Butterflies also have taste receptors on their feet, but only use them to avoid poisonous plants.
Bittel, J. (2017, August 03). Four Weird Ways Animals Sense the World. Retrieved August 06, 2017, from http://news.nationalgeographic.com/news/2014/11/141122-crabs-snakes-smell-taste-nose-science-biology/
Montell, C. (2009). A taste of the Drosophila gustatory receptors. Current Opinion in Neurobiology, 19(4), 345-353. doi:10.1016/j.conb.2009.07.001