Dec, 1905.] Chelanops oblongus. 4*1 



These two species represent the extreme in wetness to which 

 members of the order have become accommodated. 



To this hst of habitats must be added parisitism and com- 

 mensahsm, habits which the order has developed in connection 

 with other insects. 



Association with Ixsects, 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 oculatus, and others. It appears that in the tropics 

 they are more often reported upon beetles, while in the north 

 more frequently upon fhes 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 oculatus. He further 

 states that blind Chernes species travel mainly upon beetles, 

 and mentions Chelijer americanus, De Geer, on Acanthocinus 

 longimanus 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. Sanhorni 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- 



