492 Phylum Arthropoda 



The most satisfactory food used was a half lump of dry sugar placed on 

 a small i-inch square of paraffined cardboard at the bottom of the cage. 

 Water was supplied with a pipette to the sides of the cage, usually only 

 once a day. Mating of Chelonus adults was obtained in the lighted end 

 of 4-inch vials, in globe cages, and in a square box cage, but none of 

 these methods was very certain. Oviposition was secured by exposing 

 a mass of Pyrausta eggs on the floor of the female's cage for a period 

 varying from a few up to 24 hours. The parasitized egg mass was then 

 removed and placed in a small glass-covered tin box with a few leaves of 

 green dock. When the hatched borer larvae reached the 4th instar, they 

 were isolated in 3-inch glass vials plugged with cotton, and given a more 

 substantial diet of small pieces of green cornstalk, fennel plant, or string 

 beans. Chelonus cocoons spun in the vials were left undisturbed for 

 pupation and adult emergence. Both parasitized host larvae and im- 

 mature parasites were reared at a constant temperature of either 68° 

 or 77°F. with varying relative humidity. 



Bibliography 



Vance, Arlo M. 1932. The biology and morphology of the Braconid Chelonus 

 annulipes Wesm., a parasite of the European corn borer. U. S. Dept. Agric. 

 Tech. Bull. No. 294. 



REARING APANTELES THOMPSONI 



Arlo M. Vance, U. S. Bureau 0) Entomology and Plant Quarantine 



ADULTS of this parasite of the European corn borer Pyrausta nubila- 

 . Us were handled in small numbers for experimental use in a wooden 

 box cage 2 feet square and 6 inches deep, covered at one end with cheese- 

 cloth and closed at the other end by a sliding glass plate. Such a cage 

 containing Apanteles was placed with the cheesecloth toward a window 

 and the opposite side partly opened. Borer larvae of the 1st to 4th 

 instar were placed on the cage floor and each one removed after having 

 been stung by the female. Immediately after being parasitized, the 

 young borer larvae, in lots of 20 or 25, were put into small round tin 

 boxes and supplied with leaves of dock for food. They were kept under 

 such conditions at various temperatures until about the 4th instar, 

 when each was put into a glass vial and fed with stems of dock until the 

 issuance and spinning of the mature parasite larvae. The colonies of 

 parasite cocoons placed in similar vials, each containing moist blotting 

 paper or a bit of green vegetable matter, were then kept at a constant 

 temperature of either 68° or 77 F. until the adults emerged. Water 

 and drops of sugar solution were supplied the caged females. Prolonga- 

 tion of the life of A. thompsoni was best accomplished by the method 

 used by other workers of keeping the adults in a box cage in a cool dark 



