The mosquito thinks that the Salt is sugar. When he eats the Salt, he is going to get thirsty. Thinking the White Tequila is water, he drinks it and gets drunk. He starts to walk away, but he trips over the Stick, hitting his head on the Rock and dies of head injuries.
IT IS JUST THAT SIMPLE!
Ok, that is just a joke. Go to this site to find the real solution.