TRICHOPODA. 3 
In consequence of this uncertainty in the system, sometimes the most nearly-allied 
species are placed in very widely separated genera, or species which are totally different 
are united in the same genus. And this does not concern only the less-known exotic 
forms, but even the European species, which have undoubtedly been more carefully 
studied. Owing to this confusion, and also to incomplete descriptions, it is usual to 
find in most collections of Muscide many even generically undetermined specimens. 
It remains for a future monographer to solve these difficulties, and to ground a new 
system on more positive and clearer characteristics. 
Recent authors on Dipterology have, no doubt from this cause, neglected almost 
entirely the ‘ Muscide Calyptere,’ so that the numerous exotic (especially the American) 
species of this section are still, for the most part, altogether undescribed. 
In general I have adopted, with regard to the division into groups and genera, the 
classification used by Schiner in the ‘ Fauna Austriaca’ for the European species, as 
being, at the present time, the best in use. With Loew I say :—‘“ For, however insuf- 
ficient I may find the limitation of these families (groups and genera), I know nothing 
better to put in its place” (Monogr. of the Diptera of N. America, i. p. 34). I have 
nevertheless been obliged to establish some new genera for a few deviating forms. 
MUSCIDAE CALY PTERZ. 
Group PHASINZ. 
TRICHOPODA. 
Trichopoda, Latreille, in Cuvier’s Régne Anim. v. p. 512 (1829). 
1. Trichopoda pennipes, 
Musca pennipes, Fabr. Ent. Syst. iv. p. 348. 149°. 
Dictya pennipes, Fabr. Syst. Antl. p. 327. 5. 
Trichopoda pennipes, Wiedem. Aussereur. zweifl. Ins. ii. p. 274. 9”. 
Phasia jugatoria, Say, Journ. Acad. Phil. vi. p. 172. 2°; Complete Writings, ii. p. 364. 
Hab. North America }?, Indiana *, Georgia, Florida.—Muxico, Presidio (Forrer). 
A single female specimen. 
2. Trichopoda pyrrhogaster. 
Trichopoda pyrrhogaster, Wiedem. Aussereur. zweifl. Ins. ii. 272. 6°. 
Hab. Guatemata, San Gerénimo (Champion).—? Sours America }. 
A single male specimen. 
From Mexico are also described :— 
Trichopoda mexicana, Macq. Dipt. Exot., Suppl. i. p. 172. 3. 
nigricauda, Bigot, Ann. Soc. Ent. Fr. sér. 5, vi. p. 394. 1. 
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