Born in
East Hartford, Connecticut, the son of Archie and Adella (Ensign) Evans, he developed an interest in natural history, and insects in particular, as a child on his parents' tobacco farm. He attended the
University of Connecticut, where he studied English. He took an interest in biology after attending classes in entomology by
J.A. Manter. His thesis was based on rearing insects from branches broken by a 1938 hurricane. Evans next began work on a Ph.D. at
Cornell University, but his studies were interrupted by World War II. He chose to serve working as an army
parasitologist, doing pioneering work on the
Giardia parasite while stationed in
St. John's,
Newfoundland.
Giardia is a genus of microscopic parasites that cause the diarrheal illness known as giardiasis.
Giardia species (
G. intestinalis, G. lamblia, or
G. duodenalis) is found on surfaces or in soil, food, or water that has been contaminated with feces from infected humans or animals. He returned to North Carolina and worked at a base hospital studying parasites in the stools of returning servicemen. He resumed doctoral studies at Cornell with the passage in 1944 of the
G.I. Bill that helped WWII veterans and their families to cover costs for college education. He worked on the systematics of the
Pompilidae under
J. Chester Bradley and
V.S.L. Pate. Wasps in the family Pompilidae are commonly called spider wasps, spider-hunting wasps, or pompilid wasps. The family includes some 5,000 species in six subfamilies. Evans held academic positions at
Kansas State University, Cornell University,
Harvard University, and
Colorado State University. His passions included field biology, writing, teaching, the American West, backpacking, fishing, classical music, environmental conservation, and his family. Howard and Mary Alice Evans raised three children. ==Research==