Dec., 1905.] 
Chelanops oblongus. 
411 
These two species represent the extreme in wetness to which 
members of the order have become accommodated. 
To this list of habitats must be added parisitism and com- 
mensalism, habits which the order has developed in connection 
with other insects. 
Association with Insects, Food. — Pseudoscorpions evi- 
dently associate themselves with insects and a few arachnids in 
three ways: as travelers, parasites and commensalists. As 
travelers they make use of insects and other arachnids by hold- 
ing fast with the chelae of their pedipalps to the legs of flies, 
bedbugs, phalangids (harvestmen), tipulids (craneflies), etc., or 
by concealing themselves under the elytra of the larger beetles, 
Alaus ocidatus, and others. It appears that in the tropics 
they are more often reported upon beetles, while in the north 
more frequently upon flies and the other insects named. 
As supposed parasites they occur mainly upon beetles. The 
cases of Chernetidae on record, occurring under the elytra and 
wings of beetles where the body is softest, seems to make 
this belief probable. I see no reason why it should not be easy 
enough for a pseudoscorpion to penetrate the softer parts of a 
beetle with its sharp mandibles. 
In commensalism the species of insects with which they are 
associated are prboably the same as in parasitism. The truth 
is, it would be quite a difficult matter to name either the species 
of insects or of pseudoscorpions that belong strictly to any one 
of these three groups. Since pseudoscorpions are carnivorous, 
sucking the juices from smaller insects, mites, etc., it appears 
not at all improbable that they should find their prey under the 
wings of a beetle, and stay there until the supply is exhausted. 
I, myself, have found neither C. oblongus nor C. pennsyl- 
vanicus upon other insects, but Hagen (IX) reports it {Ch. alius, 
Leidy) under the elytra of the beetle Alaus ocidatus. He further 
states that blind Chernes species travel mainly upon beetles, 
and mentions Chelifer americanus, De Geer, on Acanthocinus 
longimaniis in Venezuela and South Brazil; another in Brazil on 
Passalus; and one in Melbourne (together with a tick) upon 
Passalus politus; all occur under the elytra. A special few, he 
says, travel fastened to flies, as Ch. Sanborni in Mass, and Ch. 
Loewii in Panama. Hagen evidently favors the transport 
theory and believes that certain species limit themselves to 
certain species of flies, beetles or other insects. Moniez and 
Wagner also favor the transport theory. 
Other writers favor either parasitism or commensalism. 
Thus Leydig in discussing the occurrence of a pseudoscorpion 
under the wings of a Brazilian beetle, emphasizes the fact that 
they are located under the wings where the abdomen is most 
vulnerable, and believes in parasitism. Ihering believes in com- 
