- 7 



clock turns on the defrost heater of the unit that has just gone out of 

 service, and after 1 hour it turns off the defrost heater and turns on 

 the auxiliary fan to dry the coil and return it to room temperature. 

 The auxiliary fan continues to operate until about 15 minutes after the 

 next cycle change, when the defrost cable on the other unit is then 

 turned on. 



Summary 



Especially designed cabinets are being used at Brownsville, Tex., 

 to determine the effect of different climatic conditions on the Mexican 

 fruit fly (Anastrepha ludens (Loew)) and the pink bollworm ( Pectinophora 

 gossypiella (Saund.)). 



Each cabinet has outside dimensions of about 9 2/3 by 1 1 2/3 feet 

 and 7 2/3 feet high, and consists of an inner chamber and an outer 

 chamber, refrigeration equipment, and a control panel. The insulated 

 walls are of sectional knockdown construction. 



Temperature and humidity conditions are maintained by water- 

 cooled compressors, electric strip heaters, and steam -injection 

 nozzles activated by pneumatic -electric controllers, guided by cams 

 that set the pattern of temperature and humidity to be simulated. Day- 

 light illumination is provided by infrared and ultraviolet lamps, and 

 the length of daylight is controlled by time clocks. 



To provide automatic defrosting there are two sets of cooling and 

 drying coils, operated by time clocks over intervals of 2 to 12 hours, 

 one coil being defrosted and dried while the other is in operation. 



Literature Cited 



(1) Camp, A. C. 



1955. Operation "fruit fly. " Instrumentation 7(6): 18-20. 



(2) Christenson, L. D. 



1953. Status of oriental fruit fly investigations in Hawaii. 



Exhibit C in Third Special Report on Control of the 

 Oriental Fruit Fly in the Hawaiian Islands, pp. 33-50. 

 Published by Senate of State of California. 



(3) Flitters, N. E., and Messenger, P. S. 



1953. Bioclimatic studies of oriental fruit fly in Hawaii. 

 Jour. Econ. Ent. 46: 401-403. 



(4) Harper, Robert W. 



1955. Khapra beetle and Mexican fruit fly; insect problems new 

 to California. Calif. Dept. Agr. Bui. 44: 17-28. 



