80 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
It will be noticed that the bran contained, on an average, about 
twice as many beetles as would be expected if they were equally dis- 
tributed among the five flours which were used in the experiments. 
All of the other grades of flour show such slight variations from the 
expectation that the data proved nothing with regard to selection on 
the part of the beetles. 
The invasion experiments with the larvae showed no selection. 
The percentages are all so near the expected twenty per cent that the 
differences are to be explained as chance variations. 
Series 1 Series 2 
Average of Average of 
Flour 5 counts 7 counts 
per cent per cent 
Bins middlines eee sa. oe 17.931 18.588 
ESS TASIZIMGS cso ire 17.373 17.247 
Binst lows senade) je. cmc 24.350 27233 
Binst failinas) o-satee dee. 22.435 20.272 
Bare te hs cues Srey son 17.921 16.481 
The study of the susceptibility of the wheat flour substitutes did 
not yield any conclusive evidence of preference on the part of the 
beetles. The results at hand show such an amount of variation that 
conclusions must await the results of a more extended series of experi- 
ments. In this paper two series of experiments will be introduced for 
comparison with those in which the wheat products were used. Only 
four wheat flour substitutes were used and the first low grade wheat 
flour was included for the sake of the comparison with the wheat flour 
series. 
First Second Third 
Flour eount count eount 
Pirstilow erade see scene 8 19 19 
RICE at Oli kere. Aa 24 25 33 
Barleyanl Own seer ae sean 16 17 17 
White rye flour .........: 31 33 11 
Wihiterconnth ounisesmeacre 21 22 20 
When rye meal was bolted through a No. 2 bolting cloth and the 
bran retained by the cloth was substituted for the first low grade wheat 
flour, the results were more decisive. 
First Second Third 
Flour count count count 
Ryesbpran: 64 see oe 40 33 35 
Race silos ss eee 19 17 18 
Batley tones ae ee 9 11 if 
Rye! dG 95: areemor. 14 ZA 10 
Cornel oun ene 19 17 18 
In this series there is a rather definite percentage of choice so far 
as the rye bran is concerned. As with the wheat flours it is the coarse, 
