292 INSECTA. 
of the two genera above mentioned, is amply sufficient for 
the actual wants of the science. 
Dr Desvoidy has employed but very few characters of his 
own in designating these groups. There are even some, which 
he might have used to advantage, such as the disposition of 
the nervures of the wings, which he has neglected, at least 
in the work presented to the Academy. His first family, 
that of the Calypterees, is identical with the one I call Creo- 
philes in my “ Familles Naturelies du Régne Animal’ and 
which, besides, was already established in my preceding 
works. According to the analysis of his Memoir given by 
M. de Blainville, it is evident that the characters of the 
nine other families of the Myodaires are generally founded 
on the mere diversity of their mode of habitation, their 
colours, and on some other vague considerations. 
We will endeavour to arrange the genera of Messrs 
Wiedemann and Fallen which we have been able to study, in 
our former method, but with some modifications which the 
observations of these celebrated naturalists, and others of my 
own, render necessary. 
This tribe will comprise the genus 
Musca, Lin. 
Antenne inserted near the front, palpi placed on the proboscis, and 
retiring with it into the oral cavity, and transverse nervures in the 
wings, characterize a first section of the winged Muscides, which will 
include eight principal groups or sub-tribes. 
Those of our first division, the CreopniLa, have large alule which 
almost completely cover the halteres. ‘Che wings are almost always 
distant, with the two terminal and exterior cells of the posterior 
edge(1) closed by a transverse nervure. 
(1) The most external one is situated under a narrow, elongated cell, closed by 
the posterior margin, which may be considered as a sort of cubital cell. In the 
following divisions, this exterior cell is not closed by a transverse nervure. The 
second, or that which adjoins the inner side of the preceding one, is also closed in 
the last of the Muscides; but it is no longer terminal, and frequently it is even 
