28 MUSEUM OF COMPARATIVE ZOOLOGY 



the universities of Berlin, Vienna and Paris, Hagen settled in Konigs- 

 berg as a practising physician and surgeon. This did not prevent 

 him from diligently pursuing his entomological studies, at first on the 

 dragon flies and later on the Neuroptera, at that time a heterogeneous 

 complex embracing also our modern orders Corrodentia, Plecop- 

 tera, Mecoptera and Trichoptera, and the fossil insects of the Baltic 

 Amber. During 1855 to i860 he published a masterly monograph on 

 Termites, in 1861 his well-known "Synopsis of North American 

 Neuroptera," which was prepared at the special request of the 

 Smithsonian Institution, and in 1862 and 1863 his "Bibliotheca 

 Entomologica" (2 volumes). Owing to its completeness and great 

 accuracy, this monumental work, which contains a bibliography of 

 all the entomological literature from the earliest times, is one of the 

 most useful in the entomologist's library. 



After settling in Cambridge, Hagen devoted his energies to build- 

 ing up and caring for the Museum collections and in teaching. Mr. 

 Samuel Henshaw, who was one of his most intimate friends, gives us 

 the following account of these activities: "Dr. Hagen entered upon 

 his duties at the Museum with great zeal; and his detailed plan for 

 the arrangement of the collections, though somewhat modified, is, 

 and is likely to remain, the basis for the future. Deeply interested in 

 everything relating to museum work, as his appreciation of series of 

 specimens, his care for their preservation and for the accuracy of 

 their localities, and many minor details, clearly indicate, it is in this 

 collection as well as in his writings that his contributions to science 

 are to be found. Here alone we can fully realize the extent of his 

 discoveries, the keenness of his insight, his skill at preparation and 

 dissection and with the pencil. His devotion to the Museum knew 

 no bounds; all personal interests were secondary. In 1876 he refused 

 a most flattering and urgent invitation to take charge of the great 

 entomological collections of the Konigliches Museum fiir Natur- 

 kunde in Berlin, and the time that might have been given to original 

 work was lavished upon the care and arrangement of the collections 

 which grew rapidly both in size and value. The biological collection, 

 or that illustrating the life history of the species, is a prominent spe- 

 cialty of the Cambridge Museum. In this are preserved specimens 

 showing every condition of an insect's life, the eggs, larvae in all 

 stages from those just hatched to those full grown, their burrows, 



