25 



ing a macliine that was for a short time in one of the San Fran- 

 cisco mills. We have not used sulphur nor done anything to 

 eradicate it, excepting to increase our endeavor towards clean- 

 liness." An instance of this same nature is given on p. 28, the 

 moth being introduced on some apparatus bought from a local 

 firm in whose mill the pest had a firm foothold. 



As a rule, the moth is transported carelessly on bags and 

 machinery. The former is, however, the commonest and greatest 

 source of danger, and extreme care should be taken lest the pest 

 is introduced in this manner. All bags which have been used for 

 trao sporting grain, flour, or meal should have no entry to a mill 

 until subjected to a thorough fumigation with bisulphide of car- 

 bon or with steam. Preventive measures are treated in detail 

 on subsequent pages of this paper. 



CHARACTER AND EXTENT OF INJURIES. 



The larvse of the Mediterranean flour moth would not be such 

 a pest to millers were it not for the strange peculiarity they have 

 of trailing little silken threads as soon as they begin to crawl. 

 This silk is usually mixed with flour and dust, and looks and feels 

 like a handful of cobwebs rolled loosely together in a flour bin. 



The mass of flour and web 

 represented in Fig. 4 gives 

 a fairly good idea of its 

 condition. This particular 

 material was taken from a 

 spout in a New York mill 

 last April, from which a 

 photograph was made and 

 reproduced. It is this waste 

 silk that troubles millers 

 most. When hundreds and 

 thousands of these larvae are 

 at work in a spout, elevator, 

 or other portions of machin- 

 ery, this silk accumulates 

 rapidly, piles up in tangled 

 masses, clogs the machinery, 

 and very soon stops it en- 

 tirely. Then the whole plant 

 must be taken apart and 

 cleaned. 



One of my California cor- 

 respondents sent me the fol- 

 lowing note on this subject: 

 "We find more trouble 

 with the pest in the spouts 

 and elevator legs than in 

 any other portion of the 

 mill, since these parts of the 

 ^^ .. ,^ , ., „ machinery are kept closed 



Fig. 4.— A mass of flour webbed together by the flour , , ii -u j i.u 



mothiarviE. (Original). and the moth cau breed there 



