116 
LOEW AS A DIPTEEOLOGIST 
themis and Electra among the Nemocera, and to place them, notwithstand¬ 
ing their complicated venation, at the end of the family Bibionidae. In 
that paper I thought it convenient to adopt this arrangement for the benefit 
of those who had not made the Diptera their special study, the more as the 
transition from the Nemocera to the Brachycera is effected by the Bibionidae 
on the one side, and the Xylophagidae on the other, and because, in that 
paper, I had placed the Bibionidae at the end of the one division, and 
the Xylophagidae at the beginning of the other. That the three genera, 
j Rhachicerus, Ohrysothemis, and Electra, find their natural position among 
the Xylophagidae, I have never called in doubt.” 
Such were the confused notions of Loew on the true characters 
of the two fundamental divisions of Diptera, after eighteen years 
of study of this Order! He persisted in these same notions in his 
lecture on Amber Diptera at the meeting of the German Associa¬ 
tion of Naturalists in Konigsberg (1860), and in the Preface of the 
“ Monographs North American Diptera,” Yol. I, p. 3-4, 1862. In 
this last work he says: “ It is a fact that some discoveries made 
in modern times have obliterated to a certain degree the sharpness 
of the limit which was considered to exist between the Nemocera 
and BrachyceraB And farther on: “All these facts, however, are 
not sufficient to compel us at present to give up the separation 
of the Nemocera and Braclujcera .” In my Introduction to this 
“ Record,” p. 11,1 have referred to a passage in Loew’s letter to me, 
dated July 25, 1860, in which he formally expresses the opinion that 
“ the coalescence of Nemocera and Brachycera is an accomplished 
fact,” and that he would have introduced it into the new Catalogue 
of North American Diptera, if he had been the author of it. In 
one of the last letters I received from Loew, in August, 1877 
(already quoted by me on p. 97), he mentions some of his nearly 
finished, or unfinished papers, and among them of “ preparations 
for a reform (‘Neubearbeitung’) of the System of Diptera, for the 
intended new edition of your Catalogue of North American Diptera.” 
After all the utterances of Loew quoted by me above, there can 
be no doubt that the intended reform would have consisted in the 
coalescence of the two principal divisions of Diptera! 
Loew would not have fallen into this capital error if he had con¬ 
sulted Latreilie’s “ Genera,” etc. (1809), p. 238, where the concept 
of the Nemocera Latreille (which at that time were called Tipulaires ) 
