Heir R. Kill s o)t the ruuna i J Amber. 487 



intermediate forms between gnats and Braehyceruus Hies. 

 Ilagen has more recently given us a very exhaustive treatise 

 on quite a small group of anihcr insects — the Psocida2 ; while 

 the ants have been examined by Meyer. Apart from a few 

 small memoirs, this includes the whole of the work wMiich has 

 hitherto been done on this interesting subject. Berend's 

 work on the organic remains in amber, juiblished in lS5i, is 

 of but little value for purposes of identilieation. 



The chief obstacle which has hitherto militated against the 

 proper working out of these treasures, of such extreme import- 

 ance for ])ala3ontology and zoology, lay in the fact that the 

 bnlk of the material was not selected with sufficient care and 

 was altogether insufficiently prepared. Kiinow was the first 

 to polish the pieces of amber containing specimens in such a 

 way that they can be examined with the microscope with 

 almost greater facility than preparations of existing forms. 

 It was owing to this that Ilagen, in his recent work on the 

 Psocida^, the material for which was entirely derived from the 

 Kiinow collection, was able to furnish such interesting data 

 for the phylogeny of this group from the Tertiary period to 

 the present time. In preparing the specimens as much as 

 possible of the surrounding amber was first removed, and 

 then, after polishing, they were imbedded in a hard resinous 

 matrix of a])proximately the same refractive index as amber. 

 By this means the amber enclosing the specimen is perma- 

 nently preserved from efflorescence and that loss of trans- 

 parency, which have worked such havoc among old and 

 valuable collections. Herr Klebs has so arranged this process 

 that it can be employed for the preservation of blocks of 

 amber containing a number of specimens, by which scientific 

 examination is facilitated, while the specimens themselves are 

 rendered very suitable for exhibition purposes in museums. 



After these introductory remarks llerr Klebs proceeds to 

 summarize the results of his investigations. 



Among the creatures imprisoned in amber the Diptera are 

 most numerously represented, and material to the amount of 

 at least twenty thousand perfectly preserved examples has 

 been collected. Nematocera and Brachycera are present in 

 about equal numbers. The Pupipara and Aphaniptera are 

 so far conspicuous by their absence. As regards the richness 

 in species of certain of the genera represented in amber, it 

 was found by Low that, for example. 



