86 
fusion. We prepare earth readily and in bulk in a galvanized iron 
oven 24 by 14 by1 foot. The cover is root-shaped and lifts off by a central 
handle. There is a circular orifice in this cover to emit steam and con- 
sequently to facilitate drying. The ovenstandson legs 14 feet high (the 
height being simply for conveni nce in handling) and it is heated by a 
single gas jet from a Bunsen burner placed upon a support beneath. 
After, say, two hours, heating the moisture becomes dissipated, the earth 
becomes dry and is readily sifted. It is then passed through two 
sieves, the larger one being 6 to the inch and the smaller one 18 to 
the inch. It is then in proper condition to use either in large boxes for 
underground insects or in the ordinary breeding jars or cages. 
The mention of underground insects reminds me that we have found 
the Comstock root cage a very excellent apparatus in theory but a 
difficult one to use in practice. The insects can not be observed, even 
when close to the glass side, to any advantage, since, with the slightest 
moisture, the earth becomes firmly packed against the glass, forming 
a layer which can not be penetrated by the eye. We have, therefore, 
found it more simple to rear subterranean forms in wooden boxes 2 by 
2 feet by 8 or 9 inches deep, the bottoms perforated with a few auger 
holes covered with wire netting and containing a good supply of grass 
or other food plant growing. These boxes are also made of smaller 
dimensions and, with a good supply prepared, the earth is removed at 
intervals from some and the condition of the contained insects ob- 
served. It is worthy of remark that with grass-root-feeding scarabs, 
such as Allorhina and Lachnosterna the grass crop must be kept healthy, 
or aS soon as it dies, they must be transferred to fresh boxes with 
vigorous plants. 
These same boxes make excellent rearing cages for certain insects 
attacking field crops. Four supports in the shape of laths are nailed 
to the four corners of the box and a tarletan or other gauze covering 
is constructed to fit over in such a way as to be fastened at the sides 
of the box. -The flap is left for the introduction of insects, and after 
the adults have oviposited and died the cover may be removed and the 
work of the immature stages observed at leisure. This arrangement, 
and the Riley breeding cage which has so often been figured and de-— 
scribed, are the larger vivaria. Great use is made, however, of glass — 
vessels of every size, from the small test tube, one-fourth of an inch in 
diameter by two inches long, to the large glass cylinder 18 inches high 
by a foot in diameter. One of these glass cylinders placed upon the 
slate table of the insectary, partly filled with sterilized earth and cov- 
ered with a cloth held in place by a string or rubber band, makes an 
excellent breeding cage for certaininsects. Battery jars, Mason’s fruit 
jars, jelly jars, quinine and morphine bottles and collecting tubes, all 
find their proper use. 
Another important rearing apparatus is the aquarium. Many styles — 
of aquaria have been described and are on the market. Certain special — 
. 
