TWO PRINCIPAL WORKS OF ROBINEAU-DESVOIDY 
183 
which he probably meant a condition of life) “ leads directly to 
the necessity of organs that produce that same fact” (“ainsi, 
tout se tient dans l’organisation, et la n6cessit(i d’un fait conduit 
directement aux ndcessitds d'organes qui produisent ce meme 
fait,” Myodaires, p. 23). 
The next part of the Report (p. 8-20) contains a complete 
enumeration of the numerous divisions and subdivisions introduced 
by Rob.-Desvoicly. Not only were names given by him to the 
families and tribes, but each name is followed by a short 
characterization of the group, including not only characters and 
life-habits, but the number of genera which the families or tribes 
contain. That close attention was paid by the members of the 
commission to this distribution is proved by the criticisms which 
they appended to it, and which will be reproduced below. 
From this enumeration we learn that the original plan of the 
distribution, as it was developed in Rob.-Desvoidy’s manuscript, 
was somewhat more extensive than that which appeared later in 
the volume on the Myodaires (1830). Even in this volume 
the distribution indicated on p. 20 is not entirely carried out, 
and the families eight, Micromyidae , and nine, Muciphoreae, are 
not found farther on in the letter-press. (The words of Rob.- 
Desvoidy in the Ann. Soc.. Ent. France, 1844, p. 5, evidently 
refer to this omission: “Les deux premiers tiers des Myodaires 
se trouvent imprimis en 1830 ; le dernier reste encore inedit.”) 
In the Report, the subdivisions (tribus) of the Micromyidae 
(six tribes) and Muciphoreae (four tribes) are enumerated with 
short diagnoses. Moreover, the Report mentions a tenth family, 
which does not appear at all in the 1830 volume, viz., the Cephale- 
myidae , which was to contain the Pipunculidae , and of which 
it is said “their habits are entirely unknown, and various characters 
make one suppose that they do not belong to the Myodaires.” 
This was a presentiment which has been fully justified by further 
experience. 
The rest of the Report contains criticisms and conclusions which 
I deem interesting enough for a verbatim reproduction: — 
“Such is the exact analysis, too short, its length notwithstanding, of the 
great work which Mr. Rob.-Desvoicly has submitted to the judgment of the 
