25 
ing a machine 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 
transporting 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 larvae 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 
Fig. 4.—A mass of flour webbed together by the flour m &chinery aie kept closed 
moth larvae. (Original). and the moth can breed there 
