20 BULLETIN 1028, U. S. DEPARTMEISTT OF AGEICULTUEE. 



remaining cocoons are placed in bulk in a fine copper-wire cage which 

 is nailed in a protected place in the yard until spring. 



The spring work begins during the last of April when the cocoons 

 are removed from their hibernating cage and isolated for a short 

 period in capsules. They are isolated at this time for convenience in 

 handling the adults of Apanteles and destroying the wintering second- 

 aries w^hich issue. The cocoons are isolated in the capsules less than 

 two weeks before A . melanoscelus begins issuing, and this short period 

 of confinement does not have a detrimental effect. As the adults 

 emerge they are removed hourly from the capsules and placed in 

 glass tubes 8 by 2 inches. Tlie sexes are kept separate. A sponge 

 dampened with a mixture of equal parts of honey and water is placed 

 in each tube. The tubes are then placed in a cool, dark place until 

 ready for use. 



Several different types of cages and trays have been tried as breed- 

 ing chambers with varying degrees of success. A. melanoscelus^ like 

 most hymenopterous parasites, is extremely heliotropic and indi- 

 viduals are found resting on the sides or top of the container or ex- 

 hausting themselves flying about the source of light. During the past 

 summer a breeding chamber was devised which eliminated the unsat- 

 isfactory light conditions of previous cages (PL V, A, B, C). This 

 type of breeding chamber should prove of value in breeding work 

 with other parasites. 



The empty chamber is shown in Plate V, A, resting on one side. It 

 is merely a wooden case with a glass bottom and top, with an opening 

 left in one end, through which the tray containing the larvse to be 

 parasitized is admitted. The opening is just wide enough to allow the 

 introduction of the tray and is about 2 inches deeper than the tray. 

 Cleats on which the tray is to rest are arranged inside the chamber 

 about 2 inches from the bottom. The tray should fit closely to the 

 sides and ends of the chamber, but not tightly enough to bind when 

 being introduced or removed. After the tray has beqn put in place 

 the opening in the end of the cage is closed with a tightly fitting board 

 (PL V,AatX). 



When the chamber is to be stocked with the parasites it is 

 placed on a flat surface which has previously been covered with 

 black paper (PL V, B). A piece of black paper is laid over 

 the top, covering all but 6 or 7 inches of the glass at the end 

 of the chamber facing the sun (PL V, B at L). The parasites 

 are liberated in the cage and fly to the uncovered part of the cham- 

 ber where they gather on the glass top. The tray containing the 

 small caterpillars is slid into place and is shown, part way in, in 

 Plate V, B at T. The open end of the chamber is now closed and 

 the whole thing is removed to two wooden horses, as shown in Plate 

 V, C. A piece of black paper is now placed over the entire top. 



