12 Psyche [February 
sites, have been reared in these cages, from dead wood, etc. The 
cages were kept in a green-house, in a shaded position, and the 
wood containing the insects was moistened about once a week. 
The cages have also been utilized to some extent for rearing 
army-worms out of doors. In this case the bottoms were removed 
and the cages set in soil in a shaded place. If only a small number 
of larvee are to be reared, the cages may be placed over the in- 
sects’ natural food plant, but if one is dealing with great numbers, 
the food must be renewed daily. The cages are also useful in 
making matings. Some trouble was experienced by the swelling 
or shrinking of the cage doors, depending on weather conditions. 
Test Tubes. 
For rearing fruit-flies of the genus Drosophila, test tubes (PI. 
II, fig. 2) have proven very successful. An artificial food, banana 
agar, was used. This was made by crushing four ripe bananas 
and allowing them to infuse in 500 cc. of distilled water. The 
liquid was strained and 74 grams of powdered agar added. ‘The 
whole was then cooked until the agar was dissolved. The mixture 
was poured into test tubes, after which the tubes were sterilized 
and permitted to cool in a slanting position. Non-absorbent cot- 
ton plugs were used. The flies wil! readily oviposit on this medium 
and many generations a year may be reared. A piece of filter 
paper was placed in the tubes for the maggots to pupate upon. 
Fresh tubes are used for each generation. When newly hatched 
flies are to be transferred, they are first stupefied with ether. 
The banana agar is nearly transparent which enables one to note 
the feeding habits, ete., of the larvee. 
EXPLANATION OF Puatss II anp III. 
Plate II, Fig. 1. Fruit jars used for rearing various insects. 
Plate I, Fig. 2. Test tubes used for rearing flies of the genus 
Drosophila. 
Plate III, Fig. 1. Battery jars used for rearing various insects. 
Plate III, Fig. 2. Tray with paraffin paper bottom, for rearing 
insects. 
