49 Psyche {April 
existence in his later works, as if ashamed of the curious meaningless 
names of his first publication. ‘The diagnoses are brief, general and 
ambiguous, and, since no species are mentioned the identity of the 
genera would have remained mostly unknown, were it not that some of 
the early descriptions bear a similarity to the corresponding ones of the 
later paper. In nearly all cases however the generic names of 1800 
are entirely different from those Meigen later used. ‘The genera of 
Meigen’s second contribution are well known, as for most of them 
typical species were cited at the beginning, and their names have been 
in constant usage for our commonest flies for more than a century. 
Even by this method of comparison and elimination many of the 1800 
genera will never be understood. 
This early publication of Meigen remained entirely ignored until 
Dr. F. Hendel republished it entirely in the Verhandlungen of the 
Wiener Gesellschaft. If we were to accept his guesses as to the identity 
of these early genera we would overthrow such well-known names as 
Ceratopogon, Odontomyia, Eristalis, etc., as well as the long established 
type-genera of over a dozen families of diptera. But much of his 
evidence is insecure. ‘The paper is worthless if not interpreted by 
Meigen’s later works, the date of publication cannot be verified, there 
is even doubt if the paper was distributed on the date it bears, and 
nowhere are any species cited, so the genera are uot true binomial 
conceptions. This last condition alone should not be followed too 
closely, for many of Meigen’s genera of 1803 and 1804 were likewise 
published without mention of species. 
Naturally to exhume these forgotten names has stirred up much 
discussion, and in the short interim since Hendel’s republishing, there 
have been a score of opinions given out by various biologists. “These 
opinions are sometimes conflicting but in the main zoologists strongly 
decry using the law of priority to bolster up such speciesless genera as 
Meigen’s earliest. I shall give a list of the articles that have come to 
my notice bearing directly or indirectly on the principle of whether or 
not to adopt the newly disinterred genera. In this long parley the 
concrete example of Meigen’s paper has been lost sight of by many 
of the contributors, and merely the principle has been under discussion, 
but nevertheless the entire argument outlined below was caused by 
the appearance of Hendel’s reprint. A short digest of the articles 
will help to correlate the ideas advanced. 
Professor Aldrich wrote in hopes of squelching Hendel’s paper, to 
