Charles Henry Tyler Townsend (December 5, 1863 – March 17, 1944) was an American entomologist specializing in the study of tachinids (Tachinidae), a large and diverse family of flies (Diptera) with larvae that are parasitoids of other insects.

In 1896 the USDA sent him to tropical Mexico to continue his research on the boll weevil and search for predators or parasites that might provide biological control.

He was unsuccessful in finding effective biological control agents but he did succeed in collecting a wide array of flies for his own studies.

Townsend acted as a field guide for the company, leading scientific and hunting expeditions into the Sierra Madre of northern Mexico.

[4] After the death of his wife Caroline in 1903, Townsend left his children with relatives and taught biology for two years at the Batangas Provincial School in the Philippines.

[4] After this success he turned his attention to uncovering the vector for verruga peruana and Oroya fever, diseases endemic to the mountains of Peru that were responsible for thousands of deaths.

[4] Townsend returned to the U.S. in 1914 and was employed by the USDA as a specialist on parasitic flies and curator of the Diptera collection at the U.S. National Museum.

He also completed his dissertation on the reproductive organs of the female fly and was awarded a doctorate degree by George Washington University.

Finally, in 1919 when one of his critics, John M. Aldrich, was appointed chief of the Bureau of Entomology, Townsend decided to resign his position and leave the United States for good.

Townsend and his family moved to Brazil, where he bought property in Itaquaquecetuba, including a large adobe house built in the 1600s by Jesuits.