1897 THE MICROSCOPE. 115 
their full size, and fix themselves to the pot, net, leaves, 
or twigs, or bury themselves in the earth, turning to a 
chrysalis according to its species, This is the simplest 
form of vivarium. Another plan is to procure a fern-pot 
of terracotta or earthenware, such as are sold at most 
crockery dealers. These have an inside rim, or ledge, to 
which can be fitted a cylinder of perforated zinc, so that 
it may be removed as desired. Across the top should be 
stretched a piece of muslin fastened by glue or string; an 
elastic band will also serve. In the center of this pot 
may be placed a jar (fig. 3), with perforated zinc (fig. 4), 
through which may be placed the food-plants, and the 
jar sunk in the mould or sand, with which the case 
should be filled (fig. 5). 
Many years ago I adopted a method which was most 
successful in rearing Lepidoptera from the egg, especially 
the species known scientifically as Geometre, by means 
of glass cylinders. The apparatus is simple and easily 
constructed. First procure a shallow basin, or deep 
saueer; if the latter, it should be of the largest kind 
obtainable, through the center of which a hole must be 
made, a, This may be done by placing the vessel inver- 
ted on some soft substance, as a cushion or pillow, and 
striking it sharply with the point of some instrument 
with sufficient force to make a small hole (if it can be 
drilled, so much the better). This must be enlarged so 
as to admit of a brass eyelet, such as are used by blind 
or sail-makers. Then stretch a piece of calico over the 
saucer, paste it to the underside, and fasten with a ring 
at the reverse side of the saucer. The saucer is shown 
by fig. 6. The section of the same is fig. 7, the details 
being as follows :—a, the section of saucer; b, rim over 
which the calico is stretched, and pasted at f; cis the 
calico stretched from edge b to the eyelet d; e, the hole 
in saucer. The portion of the eyelet which passes 
through the hole must be cut in such a way that the edges 
