CHART 1 CHART 
MR. F. BAI.FOUR BROWNE ON AQUATIC COLEOPTERA. 293 
ever, many of the collections made in April which were used 
in comparing March and April will not be used in comparing 
April and May and vice versa, so that the resulting curve 
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does not show anything more than the relationship' between 
one month and the months immediately preceding * and 
following it. That is, the curve shows no true comparison 
CURVES SHOWING THE NUMBER OF SPECIES PER COLLECTION 1901. k. 1905 
