KECK XT EN'JOMOI. OGICA I. I. EJEKA Ti 'RE 
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R F.C ENT ENT (1 M ( )LOG I C A ELI T E RATE RE. 
A CATALOGUE OF NORTH A.MERICAN DIPTERA. HY J. M. AI.DRICH. (Smith- 
sonian Miscellaneous Collection, Vol. XLVI, Pages 1-680, 1905.) About 
twenty years have elapsed since the publication of Baron Osten Sacken’s cata- 
logue of the North American Diptera. A catalogue such as the author now’ 
presents is one of the greatest sUniuU to the study of any group, and it should 
be possible to have such works bearing on all of the orders published more 
frequently. 
This w’ork has the same faunal limits as the Osten Sacken catalogue of 
1878, i.e. south to Panama and including the entire West Indes. 
The first and natural question to be asked was, “How many species are 
there in the new list ? ” This I could not answer, for double the number con- 
tained in the Osten Sacken catalogue does not convey a very clear idea of the 
number of species recorded, so that an actual count seemed to be the only solu- 
tion ; a single count, barring all synonyms and cross references, but including all 
“unrecognizable” and doubtful species, gave 8,191 ; if to this we add the species 
described in 1904 as given in the appendi.v (about 229), we have a total of 8,420 
species. It would be safe to cancel the 420 and to say there are probably about 
8,000 described species. 
The author’s loyalty to Baron Osten Sacken, who laid the foundation for 
dipterological study in America, is beyond question, while the following e.xpres- 
sion shows the true spirit in which a work of this kind should be produced : “I 
have been influenced by the feeling that my catalogue must represent the actual 
condition of classification not merely my own views.” A catalogue is not the 
place for radical changes, “fixity” should be the guiding star, and it is onl}' from 
this standpoint that I wish to criticise. When types exist we cannot ignore the 
species until the types have been thoroughly studied ; because the types repre- 
sent two species is no reason for dropping the name and adopting a more recent 
one, unless both species have been previously described ; species should be 
selected by elimination, the same as genera. I refer principally to Miss Gertrude 
Ricardo’s papers on the Tabanidae in the British Museum collection, published 
in the .-Xnnals and Magazine of Natural History, 1900-1902, and adopted by 
nine in his Tabanidae of Ohio. This would make the following changes in the 
