42 
SYNOPSES OF THE SPECIES. 
The arrangement of the genera is that given above. In the case of 
synonyms, the oldest name has been adopted, since this method is the 
only one whereby a uniform system of nomenclature can be obtained. 
On the other hand, if we follow the law of favoritism we can never hope 
to have a uniform series of names, since the German student will adopt 
the name proposed by a German, the Frenchman one proposed by his 
own countryman, and so on. All of the synonymy given in these pages 
has been verified by the writer. By a few authors the names of certain 
genera have been rejected, owing to the fact that the author described 
under each of them species that properly belong to two or more distinct 
genera, but this does not at all invalidate the genus, since the name 
may be retained for one or more of the species and new generic terms 
applied to the others. Again, certain genera have been rejected on 
the score that they have been insufficiently characterized, but if one of 
the species that the author placed in a given genus can be identified 
with reasonable certainty, the generic characters can readily be ascer- 
tained from an examination of the specimens themselves. 
Genera founded on characters peculiar to one sex only have not been 
adopted. The writer is of the opinion that m case the females of any 
two given species are structurally identical, these two species should 
not be separated into different genera, no matter to what extent the 
males of these two species may differ from (Mich other. Any classifica- 
tion that will not enable us to refer a single specimen of either sex to 
its correct genus must necessarily come short of the very object for 
which it was designed. 
The following pages contain references to all the species of TachinidaB 
hitherto reported as occurring in this country north of Mexico and 
belonging to genera of which the writer has examined representatives. 
Only the species studied by the writer are tabulated; the others are 
listed at the end of the tables. Genera of which the writer has seen 
no representatives, together with the species from this region referred 
to them, have already been listed on previous pages. The localities 
given are those in which the specimens studied were captured; the 
published records have not been added, since it was intended to make 
the present work as nearly original as possible. The color of the hal- 
teres has been purposely omitted as of no specific importance. 
Types of all the new species have been deposited in the United States 
National Museum. 
Genus CISTOGASTER Latr. 
Cistogaster Latreille, in (Javier's Kegne animal, Vol. V; 1829. 
rallasia Desvoidy, Kssai snr les Myodaires, p. 239; 1830. 
Gymnoclytia Brauer and Bergenstaram, Zweif. Kais. Mus. Wien. VI, p. 157; 1893. 
The synonymy of Pallasia and Cistogaster was first pointed out by 
Macquart, and has been confirmed by Rondani, Schiner, Brauer and 
Bergenstamm ? and others. Our single species is very different in the 
