MITES. 
41 
hay stored in a loft. Under these circumstances the attack proves of 
sufficient practical interest to notice. 
The general appearance of these Mites may easily be seen by any 
one who will examine a little of the living dust-like matter often to he 
found in old cheese, by placing it under a microscope or fairly strong 
magnifying glass. The order of Acarina , or Mites, are mostly very 
minute, and are distinguishable from insects in any stage by their very 
minute size, and by having head, body, and abdomen all in one piece ; 
they are for the most part furnished with four pairs of legs when they 
are full-grown, three pairs when they are just hatched. 
The subfamily of the Cheese Mites ( Tyroglyphida ) is more especially 
distinguishable by the fleshy soft whitish body, somewhat elongated in 
form, with conical proboscis; the jaws shaped like crabs’ claws 
(chelate); and the legs five-jointed, terminating in suckers or lobes 
for fixing themselves with. Amongst these Tyroglyphidce the sub-genus 
Tyroglyphus is distinguishable by having one claw, as well as the 
sucker at the end of the leg; and amongst these Tyroglyphi , the 
T. longior (the kind we have found in hay, although its special attach¬ 
ment is to various kinds of cheese) is distinguishable from the T. siro , 
the “ Common Cheese Mite,” by being larger, longer in proportion, 
furnished with much longer and more shining hairs, and also by being 
much more rapid in its movements.* The rapid movements and the 
great length of the hairs are very easily observable microscopically. 
The figure at the head of this paper shows the numerous and long 
hairs, the crabs’ claw-like jaws, and the single claw, with the fine 
sucker (“ like a sleeve”) surrounding it at the end of the tarsus or foot. 
The claw drawn (magnified) on the right-hand side is from the figure 
given in Murray’s ‘ Aptera,’ p. 256, of a tarsus of the genus Tyro¬ 
glyphus ; that on the left hand is from a sketch taken by myself of 
the tarsus, or rather the extremity of the tarsus, somewhat more 
magnified, of the specimens sent me this year (1890). It will be seen 
that the shape of this claw and the outline of the sucker precisely 
correspond with the other figure ; but I noticed the apparatus running 
up the foot for moving the claw more distinctly than appears in 
Mr. Murray’s figure, and I did not observe the cross-line apparently 
intended to show a joint. The other characteristics noted were very 
plainly observable in the specimens sent me. 
The first specimens, namely, those authoritatively identified in 
1886 by Mr. Albert Michael, together with the observations of the 
nature of the attack sent by Mr. T. Robinson, and also some general 
considerations on the habits and means of prevention of the pest, are 
• 
* For notes from which the above short descriptions of characteristics are con¬ 
densed, see Claus and Sedgwick’s ‘ Elementary Text-book of Zoology,’ and ‘ Aptera,’ 
by Andrew Murray. 
