lo Jan., 191 1 ■] Tobacco Culture. 51 



According to various writers on Entomology, the life history of this 

 moth is as follows: — The eggs hatch in six days and the larvae live about 

 a month, when they pupate. They exist from one to three weeks or longer 

 in the pupal stage, according to the temperature, after which they change 

 to the perfect moth. The average number of eggs laid by the moth may 

 be roughly estimated at a hundred. In some latitudes, there are five 

 broods per year ; and in warmer latitudes more. Based upon these facts, 

 we find that at the end of the season one female moth may become the 

 ancestor of 625,000,000 in the fifth brood, not counting those in the four 

 preceding broods. 



The principal means of spreading this destructive insect is through old 

 grain sacks. Before being taken into the mill, sacks should be shaken 

 up loosely and thrown into a tank of boiling water and allowed to remain 

 in same for a quarter of an hour. Failing this treatment, the sacks 

 should be fumigated with bi-sulphide of carbon, or hydrocyanic acid gas. 

 The boiling water is, however, the simplest and cheapest method. The 

 hydrocyanic acid gas treatment of infested mills has proved very success- 

 ful, but great care must be taken in its use; the fumes from it are deadly. 

 Any person who intends fumigating with it should first communicate with 

 the Entomologist, and obtain full particulars as to the quantity of cyanide 

 of potassium, &c. Bi-sulphide of carbon has also been used with good 

 results, but it has a tendency to make the flour sticky and, when it is in 

 sacks, the flour adheres to them. When fumigating, all openings should 

 be sealed up, so that the fumes cannot escape. Great care must be taken 

 that no light is used in the buildings during the course of treatment. 

 When finished, open all doors and windows so as to admit the fresh air. 

 It would be advisable not to enter the mill until all the fumes are gone. 



Explanation of Plate. 



I. Flour showing clusters of cocoons, pupae, and perfect insect. 



II. Larvae. 



I la. Larva in cocoon. 



HI. Pupae. 



Ilia. Pupae in cocoon. 



IV. Perfect insects. 



V. „ ,, restins. 



Natural size. From Nature. 



Since the foregoing was written. Mr. W. W. Froggatt, Government 

 Entomologist of Xew South Wales, has contributed a most interesting 

 article on the same subject to the Agricultural Gazette of Neiv South 

 Wales. Millers, especially, are strongly advised to read it. 



TOBACCO CULTURE. 



T. A. J. Smitli. Tobacco Expert. 

 {Co>itiriued from page 753, Vol. TV//.) 

 Seed Beds — continued. 

 The time for sr)\ving seed will ilipfiid on the climatic conditions nntler 

 which the grower is living, but, as a general rule, the first beds should lie 

 seeded in very early spring. It is wi.se lo have earlv plants in case a dry 

 early summer follows, but the old practice of .sowing beds in the first 

 week of July, especially in the 0\ens and King River vallevs. is a mis- 

 taken oiv. Tobacco st>e(l will not germinate until the .soil warms. Con- 

 sequently, .seed .sown before the winter is over will sinipiv remain dormant 

 luitil suitablr warmth causes tlifui to gcrminatf ; even if thev do start to 



