FAMILY CALLIPHORIDAE — 55 
Internal sexual structures of the females of the Sarcophagi- 
dae differ from those of the Calliphoridae in having a heart-- 
shaped, or cordate, uterus. This is short and has two dorsal saes, 
or pouches, developed laterally from the anteroventral walls. 
These two sacs and the uterovagina together form the uterus. 
The uterus contains eggs until the enclosed embryo has developed 
to the fully formed maggot ready for deposition. On the basis 
of the female internal sexual organs, the sarecophagid flies divide 
into at least three major groups: (1) the typical Sarcophaginae, 
as noted above; (2) the Miltogramminae, which have a thick, 
short-set V-shaped uterus, the arms of which are anterior pro- 
ductions of the lateroventral walls; and (8) the melanophorid 
genera, some of which do not have an incubating uterus but a 
uterovagina capable of incubating but a single egg, and others 
which have the more typical double-sae type of uterus. 
-EGG.. The oviparous species of Calliphoridae have from small 
to large, macrotype, more or less cylindrical, reticulate or longi- 
tudinally fluted to rather striate eggs. Eggs of Pollenia are of 
medium size; Rhinia eggs are small to medium. Those of Calli- 
phora are large, elongate, more or less cylindric, reticulate, and 
with a micropyle anteriorly, from which a shallow, dorsal groove 
extends almost to the posterior end. In Callitroga the species 
have large eggs which are elongate and ovicylindric; the dorsum 
is marked by a well-defined groove. In Cynomyopsis and Cyaanus 
the eggs are feebly striate longitudinally. 
OVIPOSITION. Blowfly females of typically saprophagous 
species usually deposit their eggs upon carrion. They will, how- 
ever, deposit upon a wide range of fresh and decaying types of 
refuse when carrion is not present. Products of bacterial action 
are not essential attrahents. Eggs of oviparous species are ap- 
parently deposited in much the same manner. Typically, they 
are deposited one at a time in rapid succession on or near food 
sources. The females extend the telescopic terminal parts of 
their abdomens and push the eggs down, one after another. The 
eggs slip into place, often completely filling a crevice, sometimes 
becoming arranged in fan-shaped masses. Under exceptional 
circumstances one or more eggs may hatch in the uterovagina and 
these may be deposited as active larvae. Eggs soon dry upon be- 
ing exposed to air, and they then stick to each other and to blown 
surfaces. When dry they have a more or less waxy appearance 
and are difficult to wet with aqueous solutions. Females often de- 
posit composite masses of eggs and numerous females depositing 
in the same localities near an attractive location may produce 
aggregate masses of thousands of eggs of one or more species, 
