August was born on February 18, 1870, in Randers, Denmark. He attended Ordrup College and Royal University in Copenhagen, from which he earned MA and PhD degrees in 1893.
From 1889 to 1893, August taught botany and zoology at both Ordrup College and Copenhagen High School. After a trip to the World’s Columbian Exposition in Chicago, he opened a flower business in Charleston, West Virginia, and became an American citizen. In 1896, he was appointed the assistant to Theodore Pergande in the Division of Entomology of the U.S. Department of Agriculture. He also became a specialist at the U.S. National Museum, working on microlepidoptera and greatly improving the museum’s collection.
He traveled frequently to Cuba, the West Indies, and Panama, surveying mosquitoes for various groups. When the Panama Canal was being built, construction had to stop several times because of malaria outbreaks. Spraying the swamplands had helped reduce the number of mosquitos but there were still a lot of problems with malaria. August was credited with discovering that the large leaves within the rain forests of Panama were collecting stagnant water and that was one of the main breeding grounds for the mosquitos. By spraying the trees, the mosquito population was kept in check during the construction of the canal. He contracted malaria during one of his visits to Central America and he suffered the side effects off and on throughtout the rest of his life.
August also went to Mexico, British Guiana, and the West Indies to study the pink bollworm, a cotton pest. In 1908 he went to England to help his friend, Lord Walsingham, prepare the volume on microlepidoptera for Biologia Central-Americana. He authored over 150 papers of his own. August retired from the U.S. National Museum in 1940, and took a Yale fellowship in Hawaii to identify microlepidoptera for the Bishop Museum there. Throughout his years of work, he described over six hundred American species of microlepidoptera. Others state that he could have named a thousand more, but he did not describe a new species unless he saw a real scientific or economic need for the differentiation.
August is remembered as going out of his way to assist friends and as having a convivial nature and a robust enthusiasm. His influence over young scientists and amateur entomologists was great.
August was elected to membership in 1903 and terminated his membership in 1910. He died on March 7, 1944.