October, '21] de ong: cold storage control 445 



which state may be reached even more quickly by sudden alternations 

 from low to high and the reverse. Experim.ents, to secure definite data 

 of this nature, were conducted on the different stages of the insects com- 

 monly attacking dried fruit, viz., Plodia inter punctella Hubn. (Indian 

 meal moth), Carpophilus hemipterus Linn, (dried fruit beetle), Silvanus 

 suriiiamensis (saw toothed grain beetle), Tenehrioides mauritanicus 

 Linn, (cadelle) and Carpoglyphus passularum Hering. (dried fruit mite). 

 No eggs were available at this time so this part of the work remains to be 

 completed. Dried prunes, raisins and figs, infested with the above 

 mentioned insects, were placed (just as the\' came from the storeroom 

 packed in 50 pound boxes) in the experimental storage plant where the 

 daily variation in temperature is less than one degree. The temperature 

 in the different rooms being 10°, 25°, 32°, 36° and 45° to 50° F. Every 

 thirty days one or two boxes of fruit were removed, their contents exam- 

 ined, and a count m.ade of all insects found and their condition noted. 

 Dead specimens were discarded to prevent their being counted the 

 second time, if it became necessary to make a count in this box in the 

 future. It was thought that this plan would better simulate conditions 

 under ]3ractical operations rather than to place a counted number of 

 insects in an artifically prepared feeding place. The total nimiber of 

 dead and living specimens was then taken as the basis for determining 

 the percentage in the table. The total number of specimens in each spe- 

 cies was not always as large as desired and as a consequence the curve is 

 not as symmetrical as it would otherwise be. A summary of the data as 

 given in Tables I and II does not distinguish between larva, pupa, and 

 adults, but in the original record the variation between the stages was 

 not great, the mature form of the larva of both beetles and moths seemed 

 to be the most resistant of any. The few mature caterpillars which 

 attempted to pupate during the storage period invariably died. 



Table I Mortality Rate By Temperature 

 (Summary of all species)' 



'Total number of specimens observed. C. hemipterus 294, S. surinamensis 1133, T. mauritanicus 35, 

 P. interpunctella 404, C. passularum 3909 (estimate). 



-The irregularity is explained by the fact that only 40 specimens were found at this examination, 15 

 of which were larvae in the room 4.5°-.50° F. 



