Harrison Gray Dyar, Jr.

Harrison Gray Dyar Jr. (February 14, 1866 – January 21, 1929) was an American entomologist. Dyar's Law, a pattern of geometric progression in the growth of insect parts, is named after him. He was also noted for eccentric pursuits which included digging tunnels under his home. He had a complicated personal life and along with his second wife he adopted the Baháʼí Faith.

Early life Dyar was born in Linwood Hill, Rhinebeck, New York, to Harrison Gray Dyar and his wife Eleonora Rosella . His father made a fortune as a chemist and inventor, and upon his death in 1875, left Dyar and the family financially independent. He wrote ghost stories for his sister Perle while his mother took a keen interest in spiritualism. The household also included Lucy Hudson, a homeopath who had a relative, George Henry Hudson (1855-1934) who inculcated Dyar with an interest in natural history. He also learned music and playing the piano from the Hudson family.

In 1880 the family moved to Boston and he attended Roxbury Latin School. Dyar went to DeGarmo Institute around 1882, founded by James M. DeGarmo who also maintained a large collection of butterflies. Dyar passed the entrance to Harvard and the Massachusetts Institute of Technology and chose the latter. He graduated from MIT in 1889 with a Bachelor of Science degree in chemistry. He had begun to study insects as a young teenager, and soon after his graduation from college began publishing scientific papers about them, in particular moths of the family Limacodidae, and subsequently Columbia University where he trained under Henry Fairfield Osborn, and where he was influenced in eugenics. He was awarded a Master of Arts degree in biology from Columbia University in 1894, with his thesis on the classification of Lepidoptera, and a doctorate in 1895, with his dissertation on airborne bacteria in New York City under the supervision of Theophil Mitchell Prudden. He was also encouraged by his sister Perle's husband S. Adophus Knopf as careers in insect taxonomy were rare. After his PhD he worked on the classification of Lepidoptera based on caterpillar morphology.

Taxonomy Dyar's lepidoptera collecting brought him in contact with Ferdinand Heinrich Herman Strecker and the Boston Society of Natural History where he was in contact with Joseph Albert Lintner and Charles H. Fernald. Dyar's early studies involved rearing caterpillars. After his major field collecting trips he began to work more intently as a taxonomist and published extensively on moths and butterflies (Lepidoptera).

Dyar's most notable work was on the number of molts of larvae published in Psyche in 1890. Dyar's Law, the biological rule named for him in recognition of his original observations on the geometric progression in head capsule widths during the larval development of Lepidoptera, is a standard approach for identifying the stage of immature insects or to predict the number of molts. An earlier publication in 1886 by W.K. Brooks independently described the same phenomenon in crustaceans, and therefore the term "Brooks-Dyar Law" (or "Brooks Rule" or "Brooks-Dyar Rule") also commonly appears in the literature.

His first job was as assistant bacteriologist of the College of Physicians and Surgeons of Columbia University from 1895 to 1897. he engaged in a "protracted, spectacularly belligerent feud with fellow entomologists". Another feud was with John Bernhardt Smith who was not careful in his application of taxonomic principles. A myth was born from the feud with Smith that the latter had named a genus of moth as Dyaria (to pun with diarrhoea). The genus was in fact erected by Dyar's friend, the amateur entomologist Berthold Neumoegen and was not in any way derogatory.

In 1924, Dyar was commissioned a captain in the Sanitary Department of the U.S. Army Reserve Officers Corps because of his background in the study of mosquitoes.

Personal life A cave-in in Washington, D.C., in 1924 revealed the existence of a tunnel built by Dyar. Dyar married Zella M. Peabody of Los Angeles, a music teacher in 1889. They had two children.

Dyar was a second cousin of American Civil War soldier and publisher Harrison Gray Otis.