122 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



inches deep. This box is fitted with two covers, the inner one glass, 

 the outer one wood. With such an arrangement it is possible to exam- 

 ine the material without allowing the insects to escape. Three holes 

 are bored in the front of the cage, one inch in diameter, and in these 

 are placed glass tubes about four inches in length. Insects attracted 

 to the light come out into the tubes, where they can be easily collected. 

 A layer of sand on the bottom of the box makes conditions favorable 

 for larvEe that enter the ground for pupation. 



. If it is desired to watch the larvre that enter the ground they are put 

 into the double tube cage. This consists of one tube inside of an- 

 other, the inner tube having no bottom. Dirt is placed between the 

 tubes and the outer tube is encased in black paper. Water placed 

 in the middle tube passes through the dirt by capillarity, keeping the 

 ground in a moist condition. This inner tube because of the light 

 forces the larvae to the outside of the outer tube, where they can be 

 readily seen by removing the black paper. 



Smaller lots of breeding material are kept in tumblers in which 

 has been placed a layer of moist sand. The tops of the tumblers are 

 covered with cheese cloth held in place by elastic bands. 



In our parasite breeding work it is desirable to obtain correct data 

 on the length of development of the various stages. In order to do 

 this each specimen is isolated and so labelled that the data on the 

 individual specimen can be referred to at any time. These specimens 

 are isolated generally as larvae or pupae in glass tubes with cotton stop- 

 pers or in gelatine capsules. 



The Dipterous parasites are somewhat harder to carry through to 

 maturity because of the lack of proper conditions of moisture. This 

 has been supplied by a new type of cage. It consists of a tray filled 

 with about an inch of sand. Glass tubes without bottoms are placed 

 in the sand in an upright position. By means of two of these tubes, 

 which are filled with water, the sand near the bottom of the tray is 

 kept wet, while the sand on the top is kept moist from this by capil- 

 larity. A single Dipterous larva is placed in each of the remaining 

 tubes, the tops of which are closed with cotton stoppers. 



Plant Cages 



Perhaps the most interesting type of cage in use at the laboratory 

 is the mica plant cage. This consists of a mica tube eight inches long 

 and two and a half inches in diameter, such as are used as chimneys 

 for gas lights. One end is closed with cheese cloth and on the other 

 end a cuff of the same material is fitted so that the tube can be placed 

 over the top of the plant and the loose end of the cuff tied tightly 



