32 
cumstances this stage is reduced to about five weeks. Mr. James 
Fletcher writes that moths kept in a breeding cage in his study, 
continued to emerge and lay eggs until December 15. He then 
adds in a foot-note, that larvse from these eggs were full grown 
March 21. This makes a period of ninety-five days, and woul i 
seem to indicate that in Canada the development of the larva is 
very much slower than in California, or in Illinois and New 
York, during the winter months, as in no case have I observed 
the larval period to last longer than forty-nine and a half days. 
When the larvse reach maturity they have the peculiar habit of 
migrating to some isolated corner for pupation, and will then 
leave their feeding quarters provided an outlet is afforded. It is 
difficult to confine them in a breeding-cage at this period, and in 
my cages many larvse have escaped by working their way out un¬ 
derneath the stout rubber bands which held the muslin over the 
cage. After maturity the larva will often crawl about for one or 
two days, without taking any food, before finding a suitable place 
for its quiescent stage. The cocoon, in which the chrysalid rests, 
is made of fine silk, often intermingled with particles of flour or 
meal. These cocoons are sometimes found in great masses in the 
most remote parts of a mill. The adult moths emerge in about 
two weeks, and deposit their eggs for succeeding generations. 
Mr. Sidney T. Klein, in a paper read before the Entomological 
Society of London, refers to the peculiar migratory habits of the 
flour moth as follows: 
“Their migratory habits, when full-fed, were very extraordinary; 
nothing seemed to keep* them within bounds. I had a colony of 
some thousands in iny house, in order to make experiments how 
to exterminate them; but I found that my breeding-cages, with 
the finest meshed wire, were useless to restrain them. I then 
placed them under a large glass shade on a polished surface with 
no perceptible outlet; but it was no use; the corners and ceiling 
of my room were within a week studded with their cocoons, and 
every day specimens of the larvse were discovered in different 
parts of the house, from top to bottom; in fact, they increased 
and wandered to such an alarming extent that I had to give up 
keeping them.” 
In the same paper, speaking of the creatures in the warehouse 
where he made his observations, Mr. Klein says: 
“When full-fed the larvse made their way to the surface, and 
could be seen in myriads crawling along the floor and up the 
walls of the warehouse, till they reached the angle where the roof 
met the walls. There they spun compact silken cocoons, in which 
they turned to the pupa state.” 
HISTORY OF THE CALIFORNIA OUTBREAK. 
In March, 1892, the president of one the largest milling firms 
on the Pacific coast invited me to visit one of his mills which, he 
said, was literally overrun with worms and moths. I inspected 
the mill the latter part of March, and procured a large number 
