104 MILL MOTH. 
flour mill where it once gets a footing, and also is to be found in 
bakeries, or the like places, where the flour, on which its caterpillars 
feed, is present; and consequently now (and for some time back) is in 
the course of unchecked spread, which has given the infestation 
thorough establishment. 
The mischief is caused by the extraordinary power possessed by 
the caterpillars of spinning up the flour into little clots, or large 
masses, of such a solid nature that these may be taken up without a 
grain of the flour falling down. The moths lay their eggs on flour or 
‘‘branny’’ stuffs, or on flour sacks, and the caterpillars (which hatch 
in a few days) in the latter case are mischievous by working through 
the sack into the outer part of the flour, and spinning it up with their 
threads; but in the mill infestation the attack is overwhelming in all 
directions. In the words of one of my milling correspondents, ‘‘ they 
get into the spouts and machinery, and do no end of mischief, both by 
destroying the silks and stopping the flow of flour, &c., in the spouts 
by spinning their web and hanging there”; and the infestation in 
moth, chrysalis, or caterpillar state may be found everywhere, whether 
in cracks or crevices, or on walls or ceilings, or infesting the machinery, 
even to the bands of the elevators, which, from the high velocity at 
which they are almost constantly running, might be expected to be 
safe from the pest. 
The moth is of the size figured, in outline, at p. 103,—that is, 
about an inch in expanse of the fore wings. The colour of these is 
erey, varying in depth of tint in different specimens, with various 
darker markings, as also figured, magnified, p. 108. The hind wings are 
whitish and semi-transparent, with a darker line along the fore edge. 
The caterpillars, which I have had from about two- to five-eighths 
of an inch in length, are cylindrical, sixteen-footed, and slender ; 
fleshy or pale red when young, almost white in the older specimens. 
The head, and a patch on the segment behind the head, yellowish 
brown; and on the last segment a brownish oval or triangular patch ; 
and along the back there were dark spots, for the most part four on 
each segment. ‘The caterpillar was slightly sprinkled with pale hairs 
or fine bristles, and had such a power of catching and retaining flour- 
dust that I had constantly to remove it by application of moisture to 
get a clear view of the markings. 
The caterpillars turn to chrysalids in silken cocoons spun in the 
flour in which they feed, and show the general appearance of the 
coming moth plainly; the colour is bees-wax below, shading to reddish 
brown on the back, and reddish brown also at the end of the tail, 
which is somewhat prolonged, slightly curved, and ending bluntly or 
cylindrically, The eyes are red. From this chrysalis state the moths 
are stated to come out in three weeks. 
