Gaborone - An 11-year-old boy was killed by a black mamba snake in the Selibi-Phikwe district in central Botswana on Wednesday, police said.The boy, his grandmother, and others had been collecting edible mopane worms in trees, Superintendent Takongwa Mazwiduma told a Sapa correspondent.The boy and his friends noticed the snake and pursued it back to its burrow. The snake turned and bit the boy. He was dead on arrival at a hospital.Mazwiduma said people bitten by snakes or other wild animals needed to report the incident to authorities quickly.In this case, the matter was reported late and it was impossible to find the snake. This was, however, the first incident of this kind in the area, Mazwiduma said.The black mamba is one of the world's deadliest snakes. It is named for the colour of the inside of its mouth.