ANGOUMOIS MOTH. 17 
In order to form a general idea of the amount of infestation that 
might be present in the sample of North African Barley sent me for 
examination, I tried the experiment of placing about a handful of the 
Barley in a bowl of water, stirring it well round in order that it might 
be all equally wetted, and noticing how much of the grain floated. 
The plan answered so well, that I should say it might be fairly trusted 
to as a guide to ascertain amount of infestation in suspected samples, 
for almost all the infested grains appeared to come to the surface. 
When the grain is in its customary dry state, the little round 
maggot-perforation in the side may, from its exceeding minuteness, 
easily escape observation; but in the test by floating, the injured 
grains are much more readily noticeable, by reason of the moistened 
outer coat of the Barley swelling, and in its expansion showing the 
perforation plainly. With regard to unperforated grain, there is little 
observable (excepting to very careful touch) to show which is infested 
or otherwise, but when moistened the infested grains will be found to 
give way before pressure from a finger-nail, and thus, where attack is 
set up, show presence of the maggot which has destroyed the sub- 
stance within. 
In regard to some sort of estimate of amount of attack present in 
the sample sent me: on placing about six and a half ounces of the 
North African Barley in water, a few light grains immediately floated 
to the surface, and after leaving the Barley undisturbed for rather over 
forty minutes, I found about eight more grains had floated, and on 
disturbing the soaking grain thoroughly, I did not find that more 
infested grains worth mentioning came to the surface. Altogether the 
grains that floated amounted to about a table-spoonful, some of which 
were certainly infested, but I did not open them all. 
In the short account of this infestation by Mr. F. H. Chittenden 
referring to its life-history in the United States of America, it is stated 
that in three weeks or more, according to season, the caterpillar attains 
maturity, and that the entire period from egg to adult state embraces 
in summer time about five weeks, and in colder weather considerably 
longer ; but also that there is ‘‘an irregular development influenced 
by temperature.” Observation is given that in the latitude of the 
district of Columbia, in an outdoor exposure, there are probably not 
more than four broods in the year, the insect hybernating as larva in 
the grain; but in a heated atmosphere there is a possibility of five or 
six generations annually. In the warmer climate of the south, where 
the insect can breed uninterruptedly throughout the winter, it has been 
estimated that as many as eight generations may be produced.* 
* See ‘‘Some Insects which are Injurious to Stored Grain.”’ Farmers’ Bulletin, 
No. 45, p. 7. By F. H. Chittenden, Assistant Entomologist, United States 
Department of Agriculture. 
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