36 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
ocellus. Not uncommonly the color of the parafrontals encroaches 
upon that of the vitta making it appear as if the sides were hollowed 
out. 
The vestiture of the back of the head when used in combination with 
other features affords characters of both generic and specific impor- 
tance. It may be entirely black as in Wohlfartia, Sarcophila, and 
probably Agria R.-Desvoidy {nee Macquart). In Ravinia and Sar- 
cophaga there is considerable variation and in some instances valuable 
specific characters are present. For example, Sareophaga dalviatina 
Schiner and S. falcidata Pandelle are easily separated by the number 
of rows of black cilia behind the eyes, the former always has one, the 
latter two. Similarly an undescribed American Sareophaga and S. 
tuberosa sarraeeniae (Riley) greatly resemble each other, but they have 
two and three rows of black cilia respectively, as above. In most of 
our genera the metacephalon bears more or less whitish or yellowish- 
white hair. This may be confined to a small portion of the plate just 
beneath the foramen as in the three species of Boettcheria here de- 
scribed, or may completely cover it (Sareophaga haemorrhoidalis, 
S. dabnatina, etc.). Often all of the plate except the very anterior 
lower corners will be thus clothed, or all but a narrow space bordering 
the posterior mouth margin. In some southern species the vestiture 
is bright yellowish or golden. 
The vestiture of the cheeks also offers both generic and specific 
characters. In Blaesoxipha it is always bristly. In Sareophaga its 
color is sometimes indicative of species groups. For example, we 
have three species of the haemorrhoidalis group as defined by Bottcher 
{Sareophaga dahnatina Schiner, S. haemorrhoidalis Meigen, S.faleulata 
Pandelle) in which it is white. Sometimes the hair on the posterior 
part of the cheek is as long as that on the metacephalon, sometimes 
shorter and distinctly marking the line of division between the two 
regions. 
The vestiture of the genae varies within wide limits. They may be 
bare, sparsely covered with short erect hairs; sometimes there are 
several rows of short hairs paralleling the lower eye orbit, or there may 
be only a short row of bristly hairs on the lower edge next the trans- 
verse impression as in Boettcheria. 
The antennae are usually inserted on a line with the middle of the 
eyes, sometimes below, but this does not seem to be of great impor- 
tance. The shape and length of the second antennal joint vary 
