412 
The Ohio Naturalist. 
[Vol. VI, No. 5, 
mensalism, and mentions species of Pyrophorotis between which 
and the pseudoscorpion he thinks a definite relation has been 
established; but he admits that the s])ecies upon leaves are 
probably the same as upon the beetles. 
As will be seen in the following topic pseudoscorjhons evi- 
dently do attack and ma}" cause the death of flies much larger 
than themselves. It occurs to me that this instinct for robberv 
is the starting point that lead to the habit of holding fast to 
insects for travel, to parasitism and to commensalism, in what- 
ever degree these exist as a habit. It is perhaps natural for a 
pseudoscorpion to lay hold of anything alive that comes within 
its reach. I have distinct recollections of teasing specimens 
with a needle or with a splinter, and that they would lay hold of 
these objects with their chelae. If, then, the attacked insect is 
strong enough to walk or fly away, and the pseudoscor])ion does 
not kill it, he becomes a passenger; if he finds natural secretions 
or succeeds in wounding his host, he is a parasite; if he finds 
other insects or mites that serve his wants, he is simply a com- 
mensalist. It is thus quite easy to understand how the three 
conditions of travel, parasitism and commensalism may have 
developed as a habit, if indeed they are not accidents, for 
pseudoscorpions can live very well without hosts. 
Food, C.\nxib.\lism.-— As I have stated before, the food of 
pseudoscor|)ions is the juices of insects, mites, etc., usually 
smaller than themselves. I have seen specimens holding some 
smaller insect either by means of the chelae of the ])edipalj)s or 
by means of the chelicerae. It is generally known that they 
feed upon psocids (corrodentia) and Hagen mentions At w pus 
pulsatorius, the death watch, as their probable food. On the 
other hand, 1 have found them {Chelijer biseriatiim) associated 
with buffalo moths and believe that they were there because the 
moths were abundant and good feeding. 
The following observations by Bachhausen are im])ortant and 
interesting. Thus Prof. C. Berg reports (V) that Bachhau.sen 
in South America found a pseudoscorpion attached to the leg 
of a blow-fly and hanging free. He noticed after several hours 
that the legs of the fly became stiff. The next morning the fly 
was dead and the pseudoscorpion sucked full under some scra])s 
of paper. Bachhausen next hungered a number u])on moss under 
a glass and then gave them some small flies. The ]>seudoscor- 
pions soon appeared from concealment and began to attach 
themselves to the legs of the flies by one pedipalj). When two 
happened to get the same fly one or the other soon let go in order 
to get a victim of its own. The legs of the flies soon become 
stiffened and when the flies died they dragged them into con- 
cealment. A tabanus is reported as dying much slower than the 
other flies. On the other hand, Muehlhausen does not find that 
