48 
LOEW’S FIRST VOLUME OF THE “MONOGRAPHS 
principal subdivision of the Diptera into Nemocera and Bracliycera 
must be given up, as soon as we attempt the introduction of a 
more or less natural system. The first I have accomplished; the 
last I have left undone, in order not to deviate too much from 
the accepted arrangement (‘ um nicht zu selir von dem Gewolmten 
abzuweichen ’)”. 
Loew was fortunate in having left undone his proposed reform 
of the system, for, far from being a progress, it would have been a 
step backwards from what Latreille had established in his “ Genera ” 
(1809), half a century before! I have exposed this error in my 
article in the Berl. Ent. Zeit., 1892, p. 421 (130, 1892) and have also 
mentioned it in the “ Introduction” of this “ Record ” (p. 11). 
The other conviction of Loew, that the venation should be consid¬ 
ered as the chief basis of classification, should likewise be accepted 
with some caution. It is in consequence of his reliance on this 
character, taken separately and without regard to the whole organ¬ 
ization, that Loew, in 1844, pointed out most unnatural affinities 
between Liponeura , Macropeza, Diamesa , Orphnephila (Chenesia 
Macq.), and Simulium ( Stett. Ent. Zeit., 1844, p. 121-122). In 
the next year, 1845 ( “ Dipterologische Beitrage,” No. I) he pro¬ 
posed his subdivision of his Tipula gallicola into Polyneura 
(Psychodidae) and Oligoneura ( Cecidomyiidae') ; and, as late as 
1860 ( “ Dipteren-Fauna Siidafrika’s ” ) he introduced his sub¬ 
division of the Cyrtidae into two sections, which proved untenable 
(all these criticisms are developed more in detail in my Chapter 
NVI: “ Characterization of Loew as a Dipterologist "). 
During this period of his career (1860-1862) Loew seems to 
have been completely in the dark about the system of classification 
to adopt. He confesses it candidly in his above-quoted letter 
(July 25,1860) and shows it in his publications. In his “ Dipteren- 
Fauna Siidafrika’s ” (1860, Preface, p. v) he acknowledges his per¬ 
plexity, and adds that his views come nearest to those of Haliday 
(in Walker’s Ins. Brit. Dipt., Vols. I—III, 1851-1856). Neverthe¬ 
less, Loew placed Thereva between Tabanidae and Asilidae, while 
Ilaliday considered Thereva as a Bombylid, which is certainly nearer 
the truth. Both authors placed the Leptidae between the Asilidae 
and Bombyliidae , which cannot be justified. 
