INTRODUCTION 29 
sericata for over 200 generations in 10 years. He observed that 
“‘these cultures have lost nothing in vigor and are well adapted 
to laboratory rearing and uses.’’ 
Female flies are brought to the laboratory in small glass vials 
with cotton plugs and transferred to incubation cages. Those 
caught in the open have usually copulated and will deposit fertile 
eggs. . 
The most convenient cage is made from a pint-size ice cream 
container with the center of the removable top replaced by a wire 
or cloth screen. Such cages are inexpensive, light, easily replaced, 
and convenient to handle. 
Adult flies must always have an ample quantity of fresh water. 
They may be fed upon small bits of banana and yeast; in fact, 
it has been found that they will live longer on this food than on 
any other. The ovaries of female blowflies will not develop if 
there is an absence of protein in their diet; this is readily sup- 
plied by placing small quantities of ground beef in their cages. 
Eggs will usually be deposited upon the under side of the 
ground beef. According to Lennox (1939), the percentages of 
eggs of Phaemcia cuprina hatching upon alkaline media are in- 
variably higher than those hatching upon acid media. Blown 
meat should be removed daily and placed upon several inches of 
slightly moistened, clean sand in another ice cream container. 
This container should be equipped with a regular top since 
mature larvae migrate and may escape through wire or cloth 
netting. | 
Ground beef is a satisfactory larval food for the carcass- 
breeding species; fat beef, owing to its high acid content, becomes 
rancid and is not favorable. Mackerras and F'reney (1933) stated 
that an alkaline reaction was apparently favorable to the devel- 
opment of blowfly larvae, while an acid reaction was compara- 
tively unfavorable. Lennox (1939) also found ‘“‘that the rate at 
which the medium is liquefied by larval growth is more rapid 
the higher the pH value,’’ and that the pH range of food media 
at which Phaenicia cuprina developed satisfactorily was wide, 
between pH 4 and 9. He found that the final reaction of the 
medium was apparently little influenced by the initial pH value. 
In all cultures in which the number of full-grown larvae was 
not less than 20 per 10 gms. of medium, the ultimate pH value 
was always between pH 7 and 8. 
It has been demonstrated within the past few years that 
saprophagous species of blowflies can be reared upon a sterile 
artificial medium. This is important to laboratories in hospitals 
where certain blowfly larvae are reared for surgical use. Lennox 
