LeConte, John L. (John Lawrence), 1825-1883

Alternative names
Birth 1825-05-13
Death 1883-11-15

Biographical notes:

American entomologist John L. LeConte was the son of distinguished entomologist John LeConte. Born in New York and educated as a physician, LeConte's inheritance meant he never had to practice medicine; instead, he continued his father's work in entomology, publishing his first paper at the age of nineteen. He travelled across the United States and later the world collecting and describing insects, especially beetles. Many of his papers were translated and republished in Europe, and the collection of specimens he and his father accumulated was one of the richest in America. He volunteered as a surgeon during the Civil War.

From the description of John L. LeConte correspondence, 1847-1861. (Pennsylvania State University Libraries). WorldCat record id: 60677988

John Lawrence LeConte was an entomologist and physician and son of naturalist John Eatton LeConte. During the Civil War, he entered the army medical corps as a "surgeon of volunteers" and was promoted to the grade of lieutenant-colonel and was medical inspector until the end of the war. He held the position of chief clerk of the United States Mint at Philadelphia, 1878-1883.

From the description of Papers, 1812-1897. (American Philosophical Society Library). WorldCat record id: 122440049

John Lawrence LeConte (1825-1883, APS 1853), entomologist was an active member of the American Philosophical Society and founding member of the American Entomological Society; a charter member of the National Academy of Sciences in 1863; surgeon and medical inspector for the U.S. Army medical corps, 1861-1865; president of the American Association for the Advancement of Science in 1874; and Chief Clerk of the U.S. Mint in Philadelphia in 1878.

John Lawrence LeConte was the son of John Eatton LeConte (1784-1860, APS 1851) an army topographer and noted naturalist, and his wife Mary Ann Hampton. John Lawrence decided at an early age to follow in his father’s footsteps, and began collecting natural specimens, showing a particular interest in insects, especially beetles. He matriculated at Mount St. Mary’s College in Emmitsburg, Maryland, graduating in 1842. Three years later he enrolled at the College of Physicians and Surgeons in New York and received a medical degree in 1846. While a medical student, LeConte also worked as an assistant to New York botanist and chemist John Torrey (1796-1873, APS 1835). Like other contemporary naturalists who were educated as doctors, including Asa Gray (1819-1888, APS 1848), LeConte seems never to have had any intention of practicing medicine. Already in 1844 he had published a paper, describing twenty-nine species of ground beetles. From 1844 to 1846 he collected specimens in the Rocky Mountains and around Lake Superior. When the noted Swiss naturalist Louis Agassiz (1807-1873, APS 1843) explored the Great Lakes area in 1848, LeConte accompanied him. In 1849, he took another trip westward, this time traveling as far as California, returning to New York in 1851.

In 1852, LeConte and his father moved to Philadelphia, whose Academy of Natural Sciences helped to make it a center of activity for the study of natural history, including entomology. Unlike his Georgia cousin Joseph LeConte (1823-1901, APS 1873), with whom John had traveled, collected specimens, and even attended medical school, he did not enter Harvard’s new Lawrence Scientific School that opened in 1847. One reason was that Agassiz, the school’s founder and premier faculty member, had no special interest in entomology. In fact, except for the work of Frederick V. Melsheimer and Thomas Say (1787-1834, APS 1817) in the first quarter of the nineteenth century, American naturalists had described and classified few insects, routinely sending specimens abroad for identification as late as the mid-1840’s. For this reason LeConte aimed to make entomology a major field of study in the United States, focusing on the order Coleoptera (beetles), which lacked an effective taxonomy. With this goal in mind, LeConte traveled widely to collect specimens, including trips to Central America and Europe. He built a extensive collection of beetles, and also published descriptions of a number of new species. LeConte was also active in scientific organizations, participating in the affairs of Philadelphia’s Academy of Natural Sciences and the American Philosophical Society. He was a founding member of the American Entomological Society and elected an honorary member of several European scientific organizations.

1861 was a momentous year for LeConte. He began work on a monograph dedicated to the classification of the Coleoptera. He also married Helen S. Grier, the daughter of U.S. Supreme Court Justice Robert C. Grier (1794-1870, APS 1848). The advent of the Civil War disrupted his scientific work and his family life. He watched in horror as his Georgia relatives joined the secessionist cause. Soon after the War began, he volunteered to serve in the U.S. Army's medical corps, first as a surgeon and later as a medical inspector. Only in 1865 was he discharged and allowed to resume his study of natural history. Two years later in 1867 LeConte joined a railroad surveying team as a geologist and zoologist. This afforded him an opportunity to study the landforms and fauna of the Great Plains and the Rocky Mountains.

During the Civil War and the years that followed, LeConte enhanced his scientific stature by participation in nationally renown scientific bodies. In 1863 he became a charter member of the National Academy of Sciences. In 1874 he served as president of the American Association for the Advancement of Science.

LeConte published two important monographs in entomology with the assistance of George Henry Horn (1840-1897, APS 1869). The first in 1876 was on the weevils or Rhynchophora of North America. In 1883 he finished his taxonomy of the Coleoptera of North America, begun in 1861. This 600-page work classified about 11,000 different beetles. Although LeConte contributed to other fields of natural history with dozens of articles on topics in geology, paleontology and ornithology, he devoted his greatest attention to the description and classification of beetles. His published studies of the distribution of insects in the American West also helped to promote zoogeography as a means of biological inquiry.

LeConte wrote studies of insect damage to crops, and in 1877 unsuccessfully sought appointment as the U.S. Commissioner of Agriculture. Despite endorsements by fellow scientists, this office eluded him. However, President Rutherford B. Hayes later appointed him the chief clerk of the U.S. Mint in Philadelphia.

John Lawrence LeConte died in his Philadelphia home on November 15, 1883 at the age of 68, after suffering a stroke. He was the father of three children, one of whom died in infancy. His contributions to entomology, in particular his taxonomy of beetles, greatly advanced descriptive and systematic entomology. Fellow entomologist Samuel H. Scudder wrote of him in 1884, “LeConte was the greatest entomologist this country has yet produced.”

From the guide to the John L. (John Lawrence) LeConte papers, 1812-1897, 1812-1897, (American Philosophical Society)

Louis Agassiz (1807-1873, APS 1843) was a zoologist and geologist. A student of Georges Cuvier, Agassiz was renown for his six-volume work Poissons fossils, a study of more than 1,700 ancient fish. Equally important was his Ètudes sur les glaciers (1840). In 1845 Agassiz moved to the United States on a two-year study grant from King Friedrich Wilhelm IV of Prussia to compare the flora and fauna of the United States and Europe. While in the United States he was invited to deliver a course of lectures at the Lowell Institute in Boston. He took America and New England by storm and as a result in 1847 was appointed professor of zoology and geology at Harvard’s new Lawrence Scientific School.

Jean Louis Rodolphe Agassiz was born in Motier, Switzerland on May 26, 1807, the son of a Protestant minister Rodolphe Agassiz and his wife Rose Mayor. Despite family pressure to enter business, Agassiz early decided to devote himself to the study of nature. At the age of twenty-one he predicted that he would become “the first naturalist of his time, a good citizen and a good son.” His determination gained Agassiz an excellent education in the natural sciences at the Universities of Heidelberg and Munich. He also made important contacts in early life that formed his outlook and provided the basis for his early career. The naturalist Johann B. Spix allowed him to publish on a collection of fish from Brazil that Spix had gathered, while the anatomist Ignaz Döllinger trained him to use the microscope and introduced him to the field of embryology. Philosophically, Agassiz was influenced by the German idealism of Lorenz Okenfuss, who built a system of biological classification based upon increasing complexity of sense organs. Agassiz’s scientific thought and practice was characterized by two separate and often contradictory outlooks. One was exact and pragmatic; the other was transcendental. His approach was clearly influenced by French zoologist and paleontologist Georges Cuvier, who passed on to Agassiz his remarkable collection of fossil fish illustrations. He also impressed the geographer Alexander Humboldt, an adviser to the king of Prussia who arranged an appointment for him at the Collège de Neuchâtel in 1832, where he taught natural history for more than ten years. During these years (1832-42) he studied fossil fish in museums and private collections throughout Europe, resulting in his six-volume Poissons fossils that described more than 1,700 primeval fish, that he analyzed according to Cuvier’s comparative method. The work, which won high praise from major Bristish naturalists Sir Charles Lyell and Richard Owen, provided the basis for Agassiz’s scientific fame and fortune. His natural philosophy was infused with the belief in an all-powerful diety, who planned and created every single living being, plant and animal, undercutting any genetic connection between ancient and modern creatures.

In addition to his work on fish, between 1837 and 1843 Agassiz did ground breaking work on glacial geology, presented in a paper presented to the Sociètè Helvétique des Sciences naturelles (July 1837) and in his book Etudes sur les glaciers in which he theorized that a massive glacier had once covered all of Europe. Although the idea had first been suggested by Swiss naturalist Jean de Charpentier, Agassiz was the first to publicize the idea and to apply it to all of Europe. A prolific writer, who wished to be personally involved with the production of his works, Agassiz developed a publishing house in Neuchâtel, that employed the latest technology in photo duplication and produced bibliographies, dictionaries and monographs by Agassiz and his assistants. In the spring of 1845 Agassiz’s fortunes abruptly shifted. His wife Cécile Braun Agassiz left her husband and Neuchâtel, his printing business closed due to accumulated debts, and he was forced to leave the Collège de Neuchâtel. Just as his luck seemed to run out, he received word of a 2-year grant secured for him by Humboldt from King Friedrich Wilhelm IV of Prussia for $3,000 to do a comparative study of the flora and fauna of the United States and Europe.

Shortly after the arrival of Agassiz in the United States, John Amory Lowell, manufacturer and head of the Lowell Institute in Boston, invited him to deliver a course of public lectures. New Englanders found the Swiss naturalist, who spoke enthusiastically about primitive fish and prehistoric glaciers, intriguing. New England scientific luminaries such as Harvard botanist Asa Gray and Yale chemist Benjamin Silliman lauded Agassiz as “full of knowledge on all subjects of science.” His lectures created such a demand for speaking engagements, that within less than two years Agassiz was able to repay $20,000 in European debt. In the fall of 1847 Harvard University offered him a chair of zoology and geology at its newly established Lawrence Scientic School. In July 1848, after his wife’s death, he arranged for his children to join him in the United States. These events, together with his 1850 marriage to a bright well-connected Bostonian Elizabeth Cabot Carey, sixteen years Agassiz’s junior, permanently anchored the Swiss scientist in America. Soon afterward Agassiz’s home in Cambridge became a center of intellectual life. As a Harvard professor he badgered the University continually for funds to build a major natural history museum to instruct the public and help to train advanced students. His efforts paid off in November 1859, when the Museum of Comparative Zoology opened its doors. The Museum provided a unique resource for American students to gain unrestricted, first hand access to natural specimens. Many practicing American naturalists of the late nineteenth and early twentieth centuries were trained by Agassiz and worked in his museum. The Museum testified to Agassiz’s passion for collecting and identifying the “entire natural kingdom all at once,” a desire that quickly filled the repository to overflowing with specimens. From a philosophical perspective Agassiz planned the Museum as a demonstration of the “master plan” that the diety had executed in the creation of the natural world, displaying the “type plan” of different classes and stressing the separate creation of each species. Agassiz’s core belief in the special creation of species by God undergirded his quest to locate new species. However, some colleagues criticized him as “species mad,” arguing that his museum and his methods added little to the conceptual understanding of natural history.

Agassiz’s reputation took a major hit in a series of Boston debates on evolution, after the publication of Charles Darwin’s Origin of Species in 1859. Agassiz made a poor defense of special creation against Darwin’s defenders Asa Gray and William Barton Rogers. Furthermore, Agassiz’s understanding of special creationism as applied to human beings led him to view various races as distinct species, a rationale quickly adopted by the proponents slavery, who asserted a scientific basis to white supremecy.

Concerned about the decline of his professional reputation in the 1850s, in 1855 Agassiz announced the forthcoming publication of a projected ten-volume entitled Contributions to the Natural History of the United States of America. A total of 2,500 subscribers made advanced purchases at $12.00 each. The initial volume entitled Essay on Classification elaborated Agassiz’s views on classification, the philosophy of nature and the species concept. Appearing two years after Darwin’s Origin of Species, the work drew mixed reviews. Many were put off by the author’s dogmatism, others thought his views dated and moribund. Three more volumes appeared, but the publication of the projected set was never completed.

Many years later in 1872 Agassiz did reconsider evolution, trying to understand Darwin’s views by making a trip around South America, retracing Darwin’s voyage. However, he only became more convinced that the concept of evolution was “a scientific mistake, untrue to the facts, unscientific in its method, and mischievous in its tendency.” To the dismay of the scientific community Agassiz authored strident attacks on Darwinism in the popular press, infuriating Asa Gray and James Dana. Consequently, Agassiz was increasingly excluded from the politics of American science.

Agassiz remained at Harvard University until the end of his life. When he died at Cambridge, Massachusetts, he was deeply mourned by his adopted country.

From the guide to the Louis Jean Rodolph Agassiz papers, 1833-1873, 1833-1873 1833-1873, (American Philosophical Society)


Loading Relationships


Ark ID:


  • Education
  • Religion
  • Entomology
  • Geology
  • Naturalists
  • Hospitals--Civil War, 1861-1865
  • Entomology--United States
  • Insects
  • Entomology--Europe
  • Medicine
  • Geology--Research--United States
  • Zoology
  • Exploration
  • Zoological museums--Massachusetts
  • Natural history
  • Scientific expeditions
  • Natural history museums--Massachusetts
  • Hospitals--United States--Civil War, 1861-1865
  • Science and technology
  • Natural history--United States
  • Medicine--Civil War, 1861-1865
  • Medicine--United States--History--19th century
  • Fossils--Collection and preservation
  • Entomologists--19th century--Correspondence
  • Mineralogy--Research--United States


not available for this record


  • United States (as recorded)
  • United States (as recorded)
  • California (as recorded)
  • Europe (as recorded)