2 Introduction. 



wilh exceptioii of oiily a few species. Tliere exsists no collections of 

 insects t'roni that time, not even O. F. Muller's, and the descriptions 

 are so siiort and incomplete that it is not possible to identify the 

 species without types. Whether O. F. Muller has ever liad a collection 

 of insects is not icnown as far as I ara aware. There is a report of 

 Hagen concerning the entomologicai collections in Denmark, Norvvay 

 and Sweden (Stett. Ent. Zeit. V, 1844, 131) in which the following 

 mention is made about tliis question: „Leider sind die sånimtlichen 

 Sammlungen und Schriften Otto Friedrich Miillers, nach denen ich auf 

 das Eifrigste geforscht håbe, ganz verscliwunden, und wahrscheinlich 

 bei den grossen Feuersbriinsten Kopenhagens oder dem Bombardement 

 untergegangen." I thinlc thai Hagen has got this information when 

 he was in Copenhagen, but now nothing is known about it. We theii 

 see the curious case that while many of Muller's species of olher 

 animals are identified, it is not so with the Diptera, of which not 

 one has been identified. The reason to this condition may be found 

 in the faet that the following authors, and especially Fabricius, have 

 paid no attention to Muller, and now nothing can be done. 



The earliest work of Fabricius: Systema Entoniologiæ, 1775, 

 enumerates 18 species, to which the locality Denmark is given, but it 

 must be remembered that a number of species are here recorded to 

 occur over the whole of Europe, and when these species of them 

 which must be taken as being known by Fabricius also as Danish, 

 are taken in consideration, we get in all abt. 190 species. The number 

 now increases steadily in the following works of Fabricius; in Entomo- 

 logia Systematica, Vol. IV, 1794, is thus enumerated 55 species from 

 Denmark, and in his last work: Systema Antliatorum, 1805, he has 

 73 species from Denmark, and with the European species which he 

 has also certainly known from Denmark, the total number may be 

 estimated at 274 species; this number Ihus represents what was known 

 of Diptera in 1805 from Denmark. 



Two works, aljout from this time, give some information about 

 Danish flies from certain localities, but have othcrwisc chiefly interest 

 as curiosities as the same holds good with regard to them, as was said 

 about the works earlier than Fabricius, viz. thai the determinations 

 cannol be relied upon. The works are: Olavius: Oekonomisk-physisk 

 lieskrivelse over Schagens Kjobsted og Sogn, 1787. in which 5 species, 

 all conmion, are recorded; and: Schade: Beskrivelse over Øen Mors, 

 1811, in wiiich there are enumerated from this litlle island the relativcly 

 great number, for this time, of 83 species. 



R. G. Stæger, the only author wlio has previously studied Danish 

 Diptera systematically, was an eager coUeclor of flies, and our know- 



