442 
ANNUAL REPORT OF NEW-YORK 
HICKORY. BARK. 
AFFECTING THE BARK. 
159 . Four-bristled mite, Oribata quadripilis , new species. (Aptera. 
Acaridte.) 
Under the loose scales of the bark, a broad oval mite of a 
shining resin-brown color and slightly transparent, with four 
small bristles projecting forward in front. Length 0.02. 
Though our knowledge of the habits of this mite is very limited 
and we are not able to say whether it is an injurious species, it 
still merits a short notice in connection with the other insects 
which occur upon the bark of the hickory. The Hickory ant 
w'hich has been mentioned above, in addition to occupying cavi¬ 
ties in the interior of the tree is met with also under the loose 
scales of the bark, in which situation numbers of them may be 
found crowded together and torpid, in the winter season And 
associated with it a small mite will frequently be found, which 
appears to be closely related to the Oribata bipilis, described by 
Hermann from specimens discovered upon the bark of a tree in 
Germany. This mite is oval and about half as broad as long, 
somewhat depressed, polished and shining, of a resin-brown color 
and slightly transparent like resin. It has in front four project¬ 
ing bristles of nearly equal length, the lower two curving inward, 
the other two straight, and a few bristles occur scattered over the 
body. The legs are also clothed with hairs of unequal length, 
and at the tip of each shank is a long bristle extending outward 
over and projecting beyond the feet. The four anterior thighs also 
have a shorter bristle at their tips, projecting outward parallel 
with those of the shanks. The four anterior legs are of equal 
length and somewhat longer than the hind ones, and the articula¬ 
ting part of their base is very narrow and slender. Their thighs 
are of an elongated ovate form, being strongly inflated into a 
kind of knot at their bases. In the winter season little groups 
of these mites are found clustered together in the crevices of the 
bark, torpid, but reviving when brought into a warm room and 
thereupon crawling about, though very slowly and awkwardly, 
the long bristles protruding out beyond the ends of its feet evi¬ 
dently serving to aid it in clinging to the surface over which it 
walks but at the same time impeding it from any briskness in its 
movements. 
