PARIvER: NEW ENGLAND SARCOPHAGIDAE. 45 
Tlu' forceps show j,'reat differences in conforiiiatioii and vcstiturc. 
Those of Ravinia are always of the type described under the external 
anatomy, the base clothed with short hairs and without upward 
fiap-like extensions and the prongs wide spread. In Boettcheria, tlie 
base bears long, fine, curly hairs in a sort of tuft, and has short flap-like 
extensions, while the prongs are more or less approximated. Sarco- 
phaga exhibits the same wide range of characters as it does for other 
structures, — they may be large or small; the vestiture hairy or 
bristly, abundant or scanty; the base may be long or short and with 
or without upward flap-like extensions; the prongs approximated for 
a part or the whole of their length, their tips l)ent forward, straight, 
curiously formed, naked or hairy. 
The accessory plates are sometimes of interest. In Boettcheria they 
do not lie entirely within the membrane but the anterior portion is 
prolonged into a linear process. In one species of Sarcophaga each bears 
a tooth-like projection. Often these plates may l)e more or less hairy 
but in S. dalmatina Schiner and S. falculata Pandelle are bare and 
shining and may often be seen distinctly without pulling out the 
genital segments. In Agria they are greatl\' modified and nearly as 
large as the forceps' prongs. 
While figures of the genitalia have been presented it is not the pur- 
pose of the author to enter into any detailed discussion concerning 
the homologies of the parts. Enlarged drawings of the penis of 
Ravinia communis are given and Bottchcr's figure showing that of 
Sarcophaga carnaria (Linne), the type species of that genus, will be 
presented in the second part of this paper. The anterior and posterior 
claspers are often of great assistance in classification. In Boettcheria 
fcrnahU and B. bisctosa 1 prefer their characters to those of the penes 
as a means of separation, for though the latter are distinct enough as 
may be seen from the drawings, their actual use in practice is another 
matter. As stated in the introduction, figures of the penes are given 
for use when other characters fail and the identification of .species by 
external characters is the object sought whenever possible. Neverthe- 
less, considerable pains and time have been taken to make the drawings 
exact. In both Boettcheria and Ravinia the penes hold quite closely 
to one txpe of construction, but those of Sarcophaga vary extensively. 
In all of these genera, however, they can be divided into proximal and 
distal portions (base and head), the former supporting the latter 
which is highly modified and presents specific characters. In Ravinia 
