76 



SCIENCE. 



[N. S. Vol. VII. No. 160. 



of only one new genus or only a few new 

 species it would yet contain descriptions of 

 all the genera and all the species of a large 

 group. He wrote few short papers and, as 

 he never was an editor, was not compelled 

 to supply ' fillers.' He believed in mono- 

 graphic work covering considerable groups, 

 or at least a large genus, and rarely wrote 

 critical or review notes. He was by no 

 means a diffuse writer, and his papers are 

 models of brevity, and of clear, succinct 

 statement. His descriptions of species and 

 genera have never been excelled, and one is 

 rarely left in doubt as to which species the 

 doctor had before him when writing. His 

 monographic and revisional papers are 

 almost all built with the evolutionary idea 

 constantly in mind. The preliminary di- 

 visions are always made upon well defined 

 structural characters, and around each tj^pe 

 of structure its derivatives are grouped. His 

 belief was that species are not isolated facts 

 or productions, but that they are parts of 

 a great scheme, which it is the work of the 

 systematist to unravel. Species are the 

 products of their surroundings, and each 

 species consists of an aggregation of indi- 

 viduals. No one specimen, to his mind, ever 

 could represent a species. It required at 

 least a male and a female, and a proper 

 definition of a species is one that would in- 

 clude also all the variations of both sexes ; 

 therefore. Dr. Horn never had a 'type' speci- 

 men, because he did not admit that any in- 

 dividual could be a type of a species. The 

 species consists of a certain combination of 

 characters ; all the individuals containing 

 this combination of characters are equally 

 types of the species ; therefore, there was 

 not anywhere in his collections any indi- 

 vidual marked as a type of any species de- 

 scribed by him. In fact. Dr. Horn never 

 considered the individual ; to him it was 

 simply an evidence of the existence of a 

 certain combination of structures, and no 

 more. A well-known Coleopterist has com- 



pared Dr. Horn's description of species to an 

 excellent portrait whose likeness to the 

 original is so great as to be recognizable at 

 the first glance. 



While the most of the work done by Dr. 

 Horn referred to the North American 

 fauna, he was yet well acquainted with the 

 general character of the Coleopterous fauna 

 of the world at large, and in his most 

 notable papers he considered our own 

 species and genera in comparison with 

 those of other countries. The two papers 

 which effectually fixed his place in the 

 first rank of workers in entomology were 

 his ' Genera of Carabidse,' published in 

 1881, and his paper on ' The Silphidse,' 

 printed in 1880. The first cited was the 

 most brilliant of the two ; the second re- 

 quired much the more painstaking labor. 

 Both of these have been accepted by all 

 students of this order. 



Dr. Horn's influence upon Coleptero- 

 logical work in North America has been so 

 great that almost all the present students 

 are following his methods wherever they 

 are doing similar work. He was a ' closet 

 naturalist,' a worker with dry specimens ; 

 he never dealt with microtomes or sections, 

 and considered life histories of subordinate 

 importance, though necessary to a complete 

 understanding of the insects in all cases. 

 Nevertheless, his work will always stand as 

 a contribution to knowledge, because it is 

 original, accurate, and, with a vital mean- 

 ing so far as it goes. It will stand the test 

 of time and of critical examination in the 

 future, for it is well done. 



His rank and standing were recognized 

 in foreign countries, some of which he vis- 

 ited several times to familiarize himself 

 with their best collections, as well as in 

 America. He was an honorary member of 

 the Societie Entomologique de Belgique, of 

 the Societe Entomologique de France, and 

 of the Entomologischer Verein in Stettin ; 

 an active member of the Societas Entomo- 



