526 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



entomologists for confining living parasites. Of these, the plain test- 

 tube, in several sizes, or the larger sterilizing tube, have been most 

 commonly used. These will always be necessary and for many pur- 

 poses of great value. However, a free circulation of air through such 

 cages is never possible. In some respects this is an abnormal condi- 

 tion for the enclosed parasites. For general breeding purposes with 

 parasites of the fruit-fly, where moist and often decaying fruit must be 

 placed with them, the elimination of gases from decajdng fruit and the 

 prevention of moisture-condensation on the sides of the cage is of the 

 utmost importance. 



The main principle involved in the construction of the tj' pes of cages 

 herein described is simply one of free-air circulation. PL 25, fig. 1 

 shows the style of cage now in use by the writers. It is invaluable as a 

 cage for the Braconid parasites now under investigation. A year's 

 trial has proved its merits over all others for most purposes in general 

 parasite work. It is of simple construction, inexpensive and easily 

 made by hand. The bottom and one end are of wood, both sides and 

 one end are of fine copper screen and the top is of glass which is fitted to 

 slide free from the cage when necessary for cleaning, as shown in 

 PI. 25, fig. 2 where the glass top has been partially drawn out. In the 

 wooden end a small opening or door is cut. The construction of the 

 door, as illustrated in PI. 25, fig. 2, has been found most satisfactory. It 

 is sawed from the piece composing the end of the cage, by two oblique 

 cuts. The cut sides of the door are then padded by covering with thin 

 strips of cardboard tightly glued on. This door then fits snugly into 

 the opening, is tighter than a hinged door and more easily made. The 

 glass top is important. This permits easy observation of the parasites 

 within, even with a binocular microscope when desired, and seems also 

 of value in allowing necessary light to enter. The cages now in use 

 are 7 by 3 by 2 inches in size. 



The three species of Braconid parasites of the fruit-fly now established 

 in Hawaii have been very successfully handled in this type of cage. 

 Oviposition and feeding is quite normal. Individual lots of parasites 

 have been kept in such cages for nearly two months without need, at 

 any time, for cleaning the cages and without any attention being given 

 them other than the dail}^ removing and replacing of leaves containing 

 drops of honey and water for food. By using such cages a great amount 

 of time is thus saved when large numbers of parasites are being handled. 

 Parasites confined in glass test-tubes must be removed to clean tubes 

 every two or three days. This is a slow and laborious process when 

 large numbers must be transferred. "Sweating" in the glass test-tube 

 containing parasites is a great annoyance and often hastens mortality 

 unless constant attention is given the tubes. This never occurs in the 



