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. His training in maths and chemistry made him organize the information in a tabular form. 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. From 1897 until his death he was honorary custodian of Lepidoptera at the U.S. National Museum, Washington, D.C. The position, though unsalaried, had been made possible by Leland Ossian Howard. He collaborated with Emily L. Morton to describe the life-histories of north American Limacodidae. His later studies were mainly on mosquitoes (Diptera: Culicidae), and sawflies (Hymenoptera: Symphyta). Dyar was independently wealthy and for a major part of his 31 years at the USNM he worked without compensation; his independence also made it possible for him to travel and collect extensively within North America. Dyar was editor of the Journal of the New York Entomological Society from 1904 to 1907 and of the Proceedings of the Entomological Society of Washington from 1909 to 1912; from 1913 to 1926 he published and edited his own taxonomic journal, Insecutor Inscitiae Menstruus. Dyar and Frederick Knab were primarily responsible for the taxonomic portions of The Mosquitoes of North and Central America and the West Indies, published, with co-author L. O. Howard, in four volumes from 1912–1917. Dyar was also noted for his intellectual and at times acerbic exchanges with fellow entomologists, for example, in correspondence with Clara Southmayd Ludlow, 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