59 THE BLOWFLIES oF NortH AMERICA 
long and is widest at its commencement, appearing more or less 
swollen at the head. In Cynomyopsis it is about one-third longer 
than the testes and rather stout, while in Lucilia the basal fourth 
is enlarged, the dilation tapered toward each end. 
The ejaculatory sac in Callitroga is usually as wide as or wider 
than the testes. In Calliphora it is rounded to oval, and in Luctha 
it is very large, flattened, and ovate. The apodeme within the 
ejaculatory bulb varies considerably in size, shape, and sculp- 
ture. I do not find it to be of any great importance in the speci- 
fie separation of these flies. It is generally more or less similar 
throughout the species known to me, in Calliphora being more 
or less typical of the entire stem. 
Genital segments of female. Except in Mesembrinellinae (the 
anatomy of which is described on page 61) the postabdomi- 
nal portion, or ovipositor, is composed of a series of small sclero- 
tized tergites and sternites surrounded by large areas of mem- 
brane, the terminal segment of which is equipped with four 
eercl. The ovipositor is capable of considerable extension and is 
totally unlike the heavily sclerotized postabdominal segments 
found in the females of typical sarcophagid ‘species. 
Internal sexual organs of the female. The internal sexual 
organs of reproduction in the female blowfly (Fig. V) as typi- 
fied by Calliphora consist of paired ovaries (O) and short ovari- 
an ducts (OD) which lead from them, these uniting to form a 
a common oviduct (CO), two long accessory glands (AG), three 
spermathecae (S), and a membranous and sclerotized uterova- 
gina (UV). The internal sexual structures of onesiine flies are 
unknown to me, but these species are said to be larviparous and, 
if so, they can searcely have the type of sexual structures de- 
scribed here. The structures in Mesembrinellinae are so modified 
that they are described in the subfamily characteristics on page 
62. 
Ovaries of typical sexually mature blowflies may nearly fill the 
posterior half or more of the abdominal cavity. Each ovary is 
oval, more or less concave on the dorsal and median surfaces 
and convex on the ventral and lateral surfaces, and is enclosed in 
a thin membrane. In Calliphora vicina, a large species, an ovary 
measures about 3.5 mm. in length, 0.3 mm. in transverse dia- 
meter, and 1.5 mm. in thickness. An ovary consists of a group 
of tapering, cylindric units which are termed “‘ovarioles,’’ and 
these are further divided into ege chambers, the foremost of 
which is smallest and most rudimentary. In Pollenia an ovary 
is composed of many ovarioles; in Rhyncomyia, of only 10 to 12, 
each about 1.5 mm. in length. In Callitroga the ovaries are com- 
posed of from 70 to 100 ovarioles each, as are those of Phormia 
