Karl von Vorse Krombein, 93, a retired senior scientist and world-renowned entomologist with the Smithsonian Institution, died of cardiac arrest Sept. 6 at Sunrise Assisted Living Center in Fairfax. Before moving to Fairfax in 1994, he had resided in Arlington County for more than 50 years.

An expert on wasps, Dr. Krombein discovered a number of species in the United States and Sri Lanka. His professional colleagues around the world named almost 90 species of insects after him. He named two of his own discoveries after his wife and one of his daughters. Family vacations alternated between coastal North Carolina and West Virginia, which provided him the opportunity for fieldwork in two diverse environments.

"My mother would have to call the general store in Nags Head to find him if there was a hurricane, because it was so unpopulated at the time," said Karlissa Krombein, one of his daughters. Over the years, Dr. Krombein also set up traps for wasps and bees throughout the Washington area in locations now covered by suburban lawns and highway concrete.

He worked for the Agriculture Department from 1941 until 1965, serving for almost 15 years as its chief of taxonomic investigations of hymenoptera, or wasps. In 1965, he moved to the Smithsonian Institution as chairman of the entomology department, a post he held until 1971. He became senior entomologist in 1971 and senior scientist from 1980. He retired in 1993, but he kept an office in the Smithsonian and continued to work full time until 1999.

He wrote or co-wrote more than 210 technical monographs, revisions and smaller papers and several books on wasps and bees.

Devoted not just to insects, the entomologist was devastated by the death of his wife of 42 years, Dorothy, in 1984. He visited her grave at Arlington National Cemetery for more than 11 years on Memorial Day, her birthday and their wedding anniversary, when he would read their wedding vows aloud at the grave, his daughter said.

Dr. Krombein was born in Buffalo. He graduated in 1934 from Cornell University, where he also received a master's degree in 1935 and a doctorate in 1960.

During World War II, he served as commanding officer for the Army's 32nd Malaria Survey Unit, stationed in New Guinea, Leyte, Luzon and Okinawa. According to a biography of him on the Patuxent Wildlife Research Center Web site, he spent six days a week in malaria research work but reserved the seventh day for collecting wasps and bees.

After the war, Dr. Krombein served in the Army and Air Force Reserves, retiring in 1979 at the equivalent rank of general officer. His awards included the Legion of Merit and the Air Force Commendation Medal.

He was a member of the Cosmos Club, the Washington Biologists' Field Club and the Entomological Society of Washington. He held fellowships with the American Association for the Advancement of Science and the Entomological Society of America.

He was also a member of Unitarian Universalist Church in Arlington.

In addition to his daughter Karlissa, of Fairfax, survivors include two other daughters, Kristin B. Krombein of Falls Church and Kyra B. Walker of Minneapolis, and four grandchildren.

Karl von Vorse Krombein was a renowned expert on wasps.