Braconidae 491 



vials of water plugged with cotton and standing upright. Diffusion of 

 water vapor prevents desiccation. Stock wasps should be removed from 

 the refrigerator every three months and fed with honey water. 



Males at room temperature may be kept alive for many days by feed- 

 ing with honey water. They become sterile after two or three weeks. 



Several matings may be made with one male which may be trans- 

 ferred after mating is observed with a hand lens. Matings are ordinarily 

 made in vials but gelatine capsules may be used if the males are weak 

 or fail to react toward females in the vials. 



A female to be set for culturing is placed in a vial with three or four 

 full grown caterpillars. The vial is set in an egg box in the incubator. 

 Caterpillars should soon be paralyzed, eggs laid within two days, and 

 maggots pupating after three or four days. 



Virgin females are obtained by placing caterpillars covered with 

 maggots on paper in petri dishes. Caterpillars may be removed from 

 vials with tweezers. Maggots will spin on the paper which may be 

 cut in order to separate the cocoons. These are then placed in gelatine 

 capsules. Adults will eclose in capsules after five days and females may 

 be transferred to vials for mating or setting. 



Caterpillars may be collected with tweezers from top or sides of 

 breeding box or from the cereal. They will congregate especially in 

 contact with the box about the edge of the cereal. If the cereal is dis- 

 turbed they will crawl about and rest on the inside of the cover or escape 

 from the box and crawl on the outside. Cereal may be removed and 

 placed on a table or sheet of paper for greater convenience in collecting 

 caterpillars. 



Virgin heterozygous females may be set for linkage tests. Wasps may 

 be etherized for examination. 



REARING CHELONUS ANNULIPES 



Arlo M. Vance, U. S. Bureau of Entomology and Plant Quarantine 



THIS parasite of the European corn borer Pyrausta nubilalis in 

 Europe was handled in small quantities for laboratory studies as 

 follows: Under warm room conditions each adult parasite was confined 

 in a small glass globe cage having a diameter of about 3 inches at the 

 middle and an opening 2 inches in diameter at each end: The top open- 

 ing was provided with a removable tin cover while the bottom was set 

 upon a piece of strong white cloth tightly stretched across a 5-inch square 

 wooden frame about an inch in height. The arrangement of the cage 

 on the cloth frame permitted a constant interchange of air with the 

 outside atmosphere and at the same time provided a suitable base to 

 which the cage could be attached by means of a strong rubber band. 



