264 



THE ENTOMOLOGIST S RECORD. 



7iiella and Corey ra ceplialonira, besides two or three other species of 

 /''phf'stia. A number of species of Coleoptera also occur, but the bulk 

 of the damage to the biscuits was caused by the first species. Closely 

 sealed tins, which had been in a colonial depot for some time, when 

 opened were found to contain only a mass of debris and dead moths. 

 Careful investigation during the manufacture and packing of the 

 biscuits showed that the only possible period of access for the moths 

 was while the biscuits were cooling from the oven previous to packing, 

 when even a few perfect insects could do incalculable damage by deposit- 

 ing their ova on a very small percentage of the biscuits, either when 

 spread over the cooling chambers, or when collected for packing. Early 

 in the enquiry it was necessary to ascertain what the temperature of 

 the biscuit was during the twenty minutes it was travelling through 

 the oven. By means of a carefully conceived arrangement of a thermo- 

 couple and a millivoltmeter, it was found that although the temperature 

 of the oven was always very considerably above boiling point, that of 

 the inside of the biscuit was never above that point. Since a 

 temperature of 69° for twelve minutes was found sufficient to cause ova 

 to fail to survive, and that access was obviously impossible after the 

 sealing of the tins, the cooling and packing periods were the critical 

 times to be put under a more perfect control. As yet the actual lowest 

 temperature sufficient to sterilise the ova has not been ascertained, and 

 it is put forward as a practical suggestion that screened cold air be 

 introduced to cool the biscuits, and at the same time to make it a 

 physical impossibility for any moth to pair and oviposit, and to remove 

 any intruding moth by revolving fans, etc. One or two important 

 biological points came out during the experiments. It was found that 

 Ephestia k'uhniella responded most readily to temperature, for while it 

 took on the average 158 days to go through its metamorphoses in the 

 British Museum, at an average temperature of 63°F, when kept under 

 observation at Washington, U.S.A., at an average temperature of 82°F, 

 the period might be as short as 38 days. This ready response to heat 

 suggested that the native habitat of the species must be a more tropical 

 area than the Mediterranean coasts. It is now practically certain that 

 the original home of this moth is the upland of Guatemala. Mr. C. G. 

 Champion records it from Panajachel, Guatemala, 3,000ft., December 

 30th, 1880, in a flour-mill of the house he stayed at for some time. 

 This is the earliest date with a definite locality, although Zeller described 

 and named the species from a specimen taken at Halle in 1877, and 

 supposed to have been introduced from America in meal. It will be 

 noticed that E. knliniella is now spoken of as the " imported flour- 

 moth," and not the " Mediterranean flour-moth " as formerly. It was 

 also proved that ('nrcijra ce/ihalonica was an oriental species intro- 

 duced freely with Rangoon rice. The Report concludes with a complete 

 bibliography and the synonymy with the descriptions of the moths 

 concerned. In addition there are five plates with figures of the imagines, 

 larviB and pup^e, with details of the characters of the head and wing 

 neuration, drawn by Mr. Durrant. It is needless to say how well this 

 work is done, for those who know the name of J. H. Durrant are 

 assured of the high and efficient character of the Report. — H.J.T. 



