Bates is most famous for his expedition to the Amazon with Alfred Russel Wallace in 1848. Wallace returned in 1852, but lost his collection in a shipwreck. When Bates arrived home seven years later (in 1859) he had sent back over 14,000 specimens (mostly insects) of which 8,000 were new to science.
Bates was born in Leicester, and at 13 he became apprentice to a hosier. He studied in his spare time, and collected insects in Charnwood Forest. In 1843 he had a short paper on beetles published in The Zoologist magazine. He became friends with Wallace, who was also a keen entomologist, and after reading William H. Edwards' book on his Amazon expedition they decided to visit the region themselves.
Henry Bates is famous for his amplification of Darwin's and Wallace's theory of evolution by natural selection. His own theory of mimicry, which now bears his name (Batesian Mimicry), provided evidence for evolution by natural selection.
From 1864 onwards, he worked as assistant secretary of the Royal Geographical Society then selling his Lepidoptera to Godman and Salvin and beginning to work mostly on cerambycids, carabids, and cicindelids. In 1881 he was elected a fellow of the Royal Society. He died of bronchitis.
In 1861 he married Sarah Ann Mason. A large part of his collections are in the British Museum. Consult The Field, London, February 20, 1892.