PARKER: XKW K.NGLANl) SARD )I'H.\( IIDAK. 40 
on the anterior face of the third femur are much refhieed or lacking 
ahogetlier, while the lower row of the posterior face is often well 
developed even when al)sent in the male. The posterior ventral of the 
middle femur is present in females of Boettcheria thouf,di not in the 
males, while in Sarcophaga thesame row is often complete in the former 
hut only present on the distal half in the latter. The number of rows 
of bristles on the middle and anterior coxae is quite constantly one 
and two respectively and does not vary as in the opposite sex. 
The abdomen is usually more oval though it may be the same shape 
in both sexes. The fourth ventral plate (taxonomic) does not show 
the adaptation met with in the male but more nearly corresponds to 
those preceding, while as a whole the sides of the plates are sometimes 
overlapped by the ventral edges of the nota. Their vestiture is short 
and bristles are borne on the posterior corners or margins. 
The genital segments very often show characters as distinctly spe- 
cific as in males, but these are less easy to define. In the females of 
Ravinia and Boettcheria these segments show the same similarity 
among the species which is so noticeable in the case of the males, while 
those of the species of Sarcophaga are well differentiated. 
Habits. 
Concerning the species of Boettcheria no information is available 
regarding the habits of larvae or adults. Those of Ravinia and 
Sarcophaga while sometimes taken on flowers are mainly scavengers 
or parasites. With some possible exceptions, the actual benefit of 
these flies as parasites is apparently open to doubt. In connection 
with the g}ipsy moth this question has been discussed by T. L. Patter- 
son and W. F. Fiske (Bull. V. S. Bureau Ent., techn. ser., 1911, no. 19, 
pt. 3). Experimental work resulted in the opinion that the species 
found associated with the earlier stages (at least in this country) are 
present in the roll of scavengers. Cases of myiasis of which sarco- 
phagid flies were the causative agent have occasionally been reported, 
but such conditions are imdoubtedly abnormal. Several species have 
been lired from human excrement and cow dung. Instances of appar- 
ent parasitism and occurrences as scavengers not previously reported, 
will follow the descriptions of species concerned. 
Systematic Section. 
Tables are given for the separation of genera and species. Preced- 
ing the former is an introductory note to prevent the confusion of 
