PARKER: NEW KNGI.AND SARCOPHAGI DAK !'!♦ 
Possibly ii close iiuiuiry into hahits might prove to be oi' xalin- in this 
connection. 8. uligiitosa Kramer, iS. simiata Meigeii, .S. .scojHtrift 
Paiulelle, Agria ajfinis Fallen, and doubtless other species are eonnnctn 
to Europe and North America. 
Raviniu is scarcely less widely distributed though not so well known. 
At least one of Van der Wulp's Mexican species belongs to this genus. 
North of Mexico there are i)erhaps seven species. Ii. hai iiuiUulen 
Meigen is the only species at present recognized from Europe and 
Africa. R. ■pallinervis Thomson has been reported from Hawaii and 
the writer has seen other species from South America. 
Boettcheria is probably more limited in its range. Three species 
are foimd in the northern United States and another in Jamaica. 
The genera Blaesoxipha and Wohlfartia are common to Europe, 
North America, and Africa. 
Generic and Sppxific Characters. 
One of the greatest difficulties experienced in working with this 
group has been to determine the value of characters; that is, which 
are generic, which specific. The writer wishes first to present in brief 
form the evidence on which his conclusions are based, many of which 
are merely tentative. 
As brought out in the previous section, Sarcophaga is a cosmopolitan 
genus. Unquestionably, then, it is very old. At the present horizon 
it is represented by many species and its specific characters are nu- 
merous and vary within wide limits; some original characters have 
probal)J\- l)een lost or altered and many new ones added as adaptations 
to changed conditions which were encountered during its dispersion. 
Some species are quite distinct, even isolated by particular characters, 
while others \yhich have several characters in common unite into 
natural groups of closely related forms. To this last statement I 
wish to call especial attention, also to the fi\-e examples of the same 
now cited. 
Group a. 
Sarcojjhaga uliginosa Kramer and S. n. sp., an American species as 
yet undescribed. These two species agree so closel\' in all external 
characters, that even the connoisseur cannot safeh' separate them 
without reference to the genitalia. Fourth ventral plate, claspers, 
