‘6 HAY MITE.” 103 
adhere to the face in a very short time, causing itchiness or irritation 
of the skin. At this stage, I think, they are less in size than they are 
when found, a fortnight or so later on, emerging from the recently 
made stacks.” 
Mr. Fraser also remarked :— 
«They have been in Rye Grass and in Meadow Grass this season, 
but more abundant in the former. During the month of September 
and early part of October they showed, or appeared to be, at their 
greatest strength and activity; after the middle of October they 
gradually showed less vitality to move or extend, until now (the 
beginning of November) all life is apparently gone.” 
This kind of Mite certainly feeds in some kinds of cheese,* and is 
noted by Canestrini as also feeding on other organic substance in a 
state of decomposition. Elsewhere it is noted as attacking an immense 
variety of dead and dried animal and vegetable substances; but I do 
not find any notes of it feeding on living vegetable matter, excepting 
possibly small fungi. But in some way or other it is obviously in 
intimate connection with the grass, or with some presence amongst 
the grass, of which the hay is made, and it would be of interest to 
trace out this point with proofs. 
From Mr. Fraser’s remark above quoted, as to alteration in size, 
the Mites appear at the season named to be approaching maturity. In 
samples sent to myself I have found young as well as fully developed 
Mites, as shown by some having only three pairs of legs instead of 
the four pairs which mark the mature condition. 
Why the Mites leave the stacks or lofts where hay is stored in 
these myriads does not appear, but the accounts agree as to the vast 
quantities in which they are to be seen on these occasions. In the 
words of one of my correspondents: ‘‘ About a month after’”’ [making 
the stack, H. A. O.] ‘there were severe frosts (15° Fahr.), and the 
following day, on each side of the stack, there was a layer, about two 
inches deep and six to eight inches wide, of these Mites’; and another 
correspondent wrote: ‘‘I could have no difficulty in sending you a 
peck of them.” 
It may be possibly worth notice that these vast emigrations out of 
the stacks seem to end (as far at least as the observations sent to 
myself go) by the Mites simply remaining heaped together outside the 
stack (or loft) instead of being sheltered within. I have not had any 
observation of their line of march elsewhere being noticed, and if 
they did remove themselves in numbers corresponding with the vast 
quantities noticed, these aggregations would (demonstrably) soon be 
dispersed. 
* See, amongst other publications, ‘ Prospetto dell’ Acaro-fauna Italiana,’ per 
Giovanni Canestrini, vol. iii. p. 407. Padova. 1888. 
