Faminy CALLIPHORIDAE 49 
(EP), the lower surface of which is smooth. The paraphallus, 
composed of membrane and sclerotized areas, has a pair of stout, 
curved, ventral struts which end distally in outwardly directed 
barbs or spurs. On the distal section of the upper wall is a 
heavily-pigmented sclerotized area, the hypophallus (HPH), 
which is partially covered in most instances with short spines, 
from which strong lateral processes, cornua, project distally, more 
or less parallel, and close to the barbed processes of the paraphalli. 
In a median line, a single process projects distally and another 
proximally to support the membrane. The praeputium is 
strengthened on the dorsal surface by the median distal process 
of the hypophallus and laterally by projections of the cornua. 
This apical section terminates in a small, funnel-like expansion 
at the base of which the ejaculatory duct opens. The phallosome 
is attached basally to the apodeme by means of a short, narrow, 
sclerotized ribbon. 
The aedeagal apodeme (A) is a strongly sclerotized, more or 
less curved rod which is often nearly as long as the phallosome. 
It is longitudinally depressed posteriorly and strongly concave 
from side to side. The anterior surface possesses a median longi- 
tudinal carina or ridge. which divides near the basal end, each 
branch terminating in a cup-like depression. The apical end is 
free, but the basal end is attached to the base of the phallosome. 
The vinculum (V) is a sclerite divided into two parts. The 
apical section is an elongate, somewhat sclerotized plate with the 
tip free; the basal section is attached to the genital segments. The 
body is a broader and more heavily sclerotized plate which ar- 
ticulates upon each side with the ‘‘quadrilateral plate’’ (Gra- 
ham-Smith, 1939), but lateral to the articulation a strongly 
sclerotized prong passes ventrally and posteriorly to form a 
bent lateral process. The lateral process articulates with the 
anterior end of a rod, which is an anteriorly directed prolonga- 
tion from the outer forceps. Aside from general habitus, some 
of these parts have not been found to be of particular value in 
the specific determination of the flies concerned and, because 
they obscure more important details, have been omitted from 
the illustrations of such parts. 
The quadrilateral plate is a median structure, concave on its 
lower surface, which articulates with the body of the vinculum 
and is fused with the anterior gonapophyses. It has usually been 
omitted from the illustrations. 
The gonapophyses are a pair of sclerotized, plate-like struc- 
tures which lie laterad of the quadrilateral plate. The anterior 
