4 NEOTROPICAL PSELAPHIDAE 



more subtle but not necessarily more mysterious influence such as aggre- 

 gation; it may be undiscernible changes in rate or character of chemical de- 

 cay; some shift in food or water conditions. In such a welter of possibilities, 

 the best approach is calm resignation in the face of barren collecting, and an 

 inquiring state of mind. 



Other, more isolated methods of taking free-living pselaphids are by 

 sweeping with a net the meadow grasses, especially bluegrass, inspecting the 

 under side of flat stones and sorting sphagnum moss. 



11. The Myrmecocoles. Since many pselaphids are myrmecocolous, ant 

 nests are desirable hunting grounds. No collection of Pselaphidae may be con- 

 sidered complete without full representation of these often highly specialized 

 and always interesting species. Examination of the ant nest requires skill and 

 patience, chiefly the latter. 



Although every log or stump may be potentially rich in mold species, few 

 of the many ant nests examined will yield pselaphid inquilines. This is not 

 because these beetles are rare, but rather because they are not so numerous 

 as their prolific hosts. Persistent search will gradually reward one by the ac- 

 cumulation of species to be taken nowhere else, e.g. all of the Clavigerinae 

 {Adranes, Fustiger), Ceo-phyllus, many species of Batrisodes, Cedius, Cerco- 

 cerus, et cetera. 



The literature dealing with specific collecting records, hosts, and pertinent 

 ecology of these forms is taken up in detail under each species {vide infra), 

 but certain general suggestions can be made here. Some pselaphids are re- 

 stricted apparently to a single host ant, or to a group of closely related hosts; 

 but since others occur with a wide variety of unrelated hosts, all ant nests 

 should be examined. In general, the more restricted the beetle to a single host 

 or group of hosts, the more specific its requirements and accordingly the more 

 specialized its structural details; some species are found over a wide variety 

 of host ants, and may even lead a free-living existence in mold as well. These 

 are less specialized usually than their restricted cousins, and such a situation 

 bears upon their structure, taxonomy, and ecology, as will be indicated later. 



The first general survey of ant and termite guests was that of the inde- 

 fatigable Wasmann, who described countless new forms, chiefly among Staphy- 

 linidae, Paussidae, and the clavigerine Pselaphidae, He was no less interested 

 in the ecology of these guests, and gave to the biology of his day the most 

 complete picture of host-guest interrelations, although he was less admirable 

 in certain of his theoretical interpretations. Wasmann's contributions may be 

 best gleaned from his publications of 1890, 1891, 1892, 1895, 1896, 1897a, b, 

 1904a, b, 1906, 1911, and 1913 of the bibliography. Wasmann (1894) lists over 

 twelve hundred inquilines of ants and termites, and his contribution is further 

 treated by Wheeler (1923, 1928). The origin of myrmecophily is discussed by 

 Wasmann (I.e.), Wheeler (I.e.) and Donisthorpe (1909, 1927). Donisthorpe 

 has reviewed (1927) the British ant guests, among which pselaphids are dis- 

 cussed. 



