1^99] RUST-RED FLOUR BEETLE. 53 



several broods are generated in the course of a year. From observa- 

 tions conducted by the writer" [Mr. F. H. Chittenden— E. A. 0.], 

 "it has been learned that this insect is capable in an exceptionally 

 high temperature of undergoing its entire round of existence from egg 

 to imago in thirty-six days. The minimum period of incubation was 

 not ascertained, but it may be assumed as about six days. This, with 

 SIX days for the pupal period, gives twenty-four days as the shortest 

 developmental period of the larva. In cooler weather these periods 

 last two or three times as long. In well-heated buildings in a latitude 

 like that of Washington we thus have the possibility of at least four 

 generations in a year." * 



Looking at the circumstance that it is very recently that the two 

 above-named species of beetle have been considered to be oiher than 

 all of one kind, and that still they are recorded as closely resembling 

 each other in colour, size, form, habits, and life-history, their preven- 

 tive treatment may be laid down safely to be similar. 



Prevention and Eemedy. — A very important point in household 

 or store' treatment is scrupulously cleaning all barrels, tubs, lockers, 

 bins, or other wooden depositories in which flour or grain that has 

 been found to be infested by Flour Beetles may have been kept. A 

 thorough " scrubbing " applied with scaidiiir/ hot ivater by a good hard 

 scrubbing-brush of the make with a few rows of longer bristles at one 

 end, so that all chinks and crannies could be well cleared out, would 

 probably be very effective. If soft-soap and a little mineral oil of any 

 kind could be used in solution in the scalding water without danger of 

 tainting the flour which might subsequently be placed in the cask or 

 other wooden receptacle, — this of course would be a great additional 

 safety. 



The transmission of attack in connection with infested bags or 

 packages is a most fertile source of mischief. Independently of bags 

 containimj flour, those that are returned empty convey the infestation, 

 whether of the special kinds of Flour Beetles under consideration, or 

 the " Granary Weevils," or the " Mediterranean Mill Moth " in legions ; 

 and it is not only in traffic to and fro, but where these infested bags 

 are used without jjroper purijication as ship packing material (technicallv, 

 I believe, known as "dunnage"), that enormous mischief is done. 



I have no record of this precise form of trouble having arisen with 

 regard to the Tribolium beetles ; but with regard to the Calandra, 

 or Granary Weevils, observation has been put in my hands of 

 the weevils being so swarming in the dunnage as to fall down the 

 men's backs in the packing operations. This might be completely 

 obviated, whether with the Tribolium or other infestation, by placing 

 * See ' Household Insects,' referred to, ante, at p. 51. 



