12 
WORK IK EUROPE 
In my “ Historical and critical remarks concerning Loew’s first volume of the 
£ Monographs of North American Diptera,’ etc.,” in this “ Record,” Part II, Chapter 
VII, I have reproduced a passage of his letter to me, dated July 25, 1860, in 
which he formally expressed his opinion that the coalescence of Nemocera and 
Brachycera was an accomplished fact, and that he would have introduced this 
innovation in the new Catalogue of North America Diptera, if he had been the 
author of it ! 
(2) The other innovation, introduced by me in my 130 (1892), 
was to show that, within the three suborders, the existing families 
of Diptera could be easily arranged into larger groups, which I 
called Divisions , but which, since the appearance of Prof. J. H. Com¬ 
stock's Manual, etc. (1895), I prefer with him to call Superfamilies. 
I called attention to characters which the families belonging to 
such superfamilies have in common; characters of which most 
had heretofore been entirely overlooked or neglected. The impor¬ 
tance, for instance, of the character derived from the structure of 
the head in the male, which I called lioloptic , had never been 
sufficiently appreciated before, so much so that there was no 
special term even to designate this structure. The total absence 
of this character in my superfamily Nemocera vera , combined with 
several other characters borrowed from different parts of the body, 
as well as from the early stages, justifies the separation of this 
Division from the superfamily Nemocera anomala , so called because 
I placed in it a number of anomalous, ancestral forms, not having 
any apparent connection between them. At the same time, there 
is no doubt that both superfamilies belong to the same suborder 
Orthorrhapha Nemocera. 
Within the suborder Orthorrhapha Brachycera I have formed, 
for the families Stratiomyiidae , Tabanidae , Acanthomeridae , and 
Leptidae (including the Xylophagidae), the superfamily Eremo- 
chaeta , characterized by the predominance of lioloptic heads in 
the male sex, and by the remarkable instability in the structure 
of the antennae, a character which I have called “ morphological 
restlessness A conspicuous peculiarity of this superfamily is the 
total absence of macrochaetae , from which 1 have derived its name. 
Other characters are taken from the legs, provided, in most cases, 
with three pul villi; from the wings, which in most cases have five 
posterior cells ; and from the shape of the more or less developed 
