22 MUSEUM OF COMPARATIYE ZOOLOGY. [Apr. 



The object of this kind of work is chiefly as a preparation for 

 further study in this direction, and for the use of students who 

 wish to devote their time to like investigations. Chiefly for this 

 purpose the writer of this Report has ordered and imported new 

 French and German microscopes of a low-stand pattern, recog- 

 nized in Europe as the most fitting for such work. Some of 

 them, paid for many months ago, have not yet arrived ; es- 

 pecially the Gundlach objective, noticed in German and English 

 papers as the strongest now known. After careful examination 

 and many test experiments I have nearly completed the neces- 

 sary arrangements for securing as useful and at the same time 

 as cheap a collection of instruments as possible, and I hope in 

 a few months that I shall be able to furnish to students an ex- 

 tensive plan for microscopical study. The Museum will then 

 be provided with American, French and German microscopes 

 of the best kind and power, with working lenses, especially 

 Prof. Bruecke's working lens, not hitherto known here; also 

 different kinds of instruments for drawing by the microscope 

 and the best test objects, as Nobert's newest test plates and 

 Miller's greatest Diatom plates, imported especially for the 

 instruction of students. 



The Library of the Museum has received by purchase a very 

 valuable addition in the entomological works belonging to the 

 late Dr. Zimmermann, of S. Carolina, containing chiefly coleop- 

 terological books. It was thought more convenient to unite in 

 the entomological room, in the Museum, all works belonging to 

 this department, from the library of the Museum as well as those 

 from the private library of Professor L. Agassiz and my own. 

 They are arranged alphabetically and a separate catalogue is 

 ready. The portion of this library relating to the insects of 

 North America is set aside for students, and everything is done 

 to make it hereafter as complete as possible. 



The alcoholic collection is revised and in tolerable condition. 

 Further progress in it was not possible for want of time.* 



* After this Eeport had been handed in, Dr. Hagen received the gratifying intelligence 

 that Baron d'Osten Sacken has presented to the Museum his whole collection of GaUs, of 

 Cynipidse or Gall-producers and their parasites. The collection contains aU the species 

 thus far found in the United States, and is the more valuable because all are types de- 

 scribed by the Baron in his excellent papers upon this matter in the Proceedings of the 

 Philadelphia and Stettin Entomological Societies. There exists no collection in the world, 

 so far as I know, so complete and so carefully worked out as this. As the Museum already 

 possesses the types of American Galls described by the late Mr. B. Walsh, this gift from 

 Baron d'Osten Sacken now gives unquestionable superiority to our collections in this im- 

 portant department of Natural History, 



