THE LARVARIUM 237 
baseboard being fairly heavy the cage stands firmly, 
and is not readily overturned. The perforated zinc 
sides admit plenty of air. The glass at the back is 
fixed, while the front glass slides in grooves, and 
can be completely removed when I desire to clean 
the cage, change the food, and so forth. The food- 
plant in this cage is placed in a jar of moist sand. 
You may, however, make better provision than is 
made in the cage illustrated. When you have to 
invent something for Nature-study purposes, make 
up a list of requirements, and invent accordingly. 
You have some larve. Ask yourself what larve 
require. They need food and air; then arrange 
for a proper supply of both. You wish to keep the 
food fresh; then supply it with moisture. The 
larve will change into pupe. Some will make 
cocoons in corners of the cage ; others will want to 
bury themselves. For the latter you must provide 
sand, loam, cocoanut fibre, moss—whatever you 
deem most suitable. Then you must so construct 
your cage that your captives cannot escape. In the 
cage I have described there is no sand or moss 
provided for the “change.” Then it might be 
improved by having two chambers in the bottom, 
one containing sand, fibre, or moss for the “‘ change,” 
and another to hold vessels of water or moist earth 
for the benefit of the food-plants. This chamber 
should be covered with a lid in which a few small 
holes are made to admit the stalks of the plants. 
When the perfect insects emerge from the pupa 
state you may allow the females to leave you some 
eggs from which to rear more specimens, or, having 
had the satisfaction of watching their developments, 
