200 



[ Fchruaiy, 



is truly more apparent than real ; for, though many species are ex- 

 ceedingly alike, when closely examined, good distinctive characters 

 may mostly be found for their separation. 



To facilitate their examination and description, it is imperatively 

 necessary to sub-divide them into groups or genera ; and though some 

 of these must be more or less artificial, this is a small evil in com- 

 parison with leaving 200 or 300 species in one genus. 



It is for the purpose of calling the attention of British entomolo- 

 gists to this family (which has been most carefully studied upon the 

 Continent) that I venture to publish a few remax'ks on the characters 

 of the principal generic sub-divisions into which our indigenous spe- 

 cies may be classed, and I shall endeavour to arrange them, as far as 

 possible, into natural groups. 



Meigen, to whom all Dipterologists owe so much, first detached 

 these flies from the great tribe of MuscidcB ; but he retained almost all 

 the European species in one genus, which he named Anthomyia. In 

 his seventh or supplementary volume, however, published in 1838, he 

 raised them to the rank of a separate family, and adopted some of the 

 new genera which had then been formed. 



Dr. Eobineau Desvoidy, in his " Essai sur les Myodares " (1830), 

 first sub-divided this family (which he named Mesomydce) into a great 

 number of small groups ; but he went as much too far in the formation 

 of genera as he did in the sub-division of species, for both are charac- 

 terised by such insufiicient and undecided characters, that they are 

 practically useless. Macquart* reduced the chaos created by Desvoidy 

 into something like order, and his genera (which were made with great 

 skill) have been adopted, with various modifications, by most subsequent 

 authors, with the exception of Zetterstedt, who, in his great work upon 

 the Dipfera of Scandinavia, includes almost all the AntJiomi/iidce in two 

 genera ; one characterised by having entirely black legs, and the other 

 by the logs being partly or wholly yellow. 



Rondani, the most recent systematic writer upon the AntJiomyiidoB, 

 has, in his work upon the Italian Dipfera, very carefully and elabo- 

 rately i-evised the genera into which they may be sub-divided, adding 

 a good many new ones, and altering the names of others ; and, although 

 he may have carried his alterations a little too far, he has done much 

 valuable work.f 



The Anthomi/iidcv may at once be known from the typical flies 



* Hist. Nat. lies insectes diptferes, 1835. 

 t Schiner's valuable work upon the l)ij)te)-a , in the " Fauna Austriaca," may also be uieutioned. 



