a 
(20 NEW YORK STATE MUSEUM 
approximately one day for each 100 feet of elevation. The 
method of reaching this conclusion is as follows: the 3° differ- 
ence in latitude between the two places gives an allowance of 12 
days, that is four for each degree of latitude, and as Genesee 
county is farther north, the 12 days may be subtracted from the 
date given for Columbus, but before subtracting this, the date 
for Columbus must be brought down to a sea level calculation, 
‘and as that date is September 25 at 800 feet above sea level, the 
safe date must be eight days later, or approximately one day 
later for each 100 feet less in elevation. This brings the safe 
date at Columbus O., were it at sea level, at October 3, and 
bringing this date forward 12 days, the allowance made for the 
8° difference in latitude, we have the normal date for Genesee 
county in localities at sea level. This date, September 21, may. 
then be advanced one day for each 100 ft elevation above sea 
_levei. 
At first sight this rule may appear a little cumbersome, but it 
is really a very simple one and it certainly deserves a trial by 
every farmer troubled with the Hessian fly. If it accomplishes 
nothing more, it gives a basis on which to begin experiments, 
and we are therefore able to approximately figure the safe date — 
for any locality and then this should be checked up by past expe- 
riences or put to the test of future use. The farther north the 
location and the higher the elevation, the earlier may the wheat 
be sown with safety. 3 
- Parasites. The parasites of the Hessian fly are very important, 
since were it not for them it is extremely probable that it would 
be much more destructive than it is. The easiest way to deter- 
mine the proportionate number of parasites in any one field is 
to take infested stalks and breed the adult insects from them. 
A net-covered jelly tumbler or fruit jar, taking care to avoid 
close covers and resulting molds, will answer very well as a 
breeding cage. Later in the season, after the parasites have 
emerged under natural conditions,an examination of “flaxseeds”’ 
in the field will give some idea of the relative number which have 
been killed by these tiny friends of man, since each having a cir- 
