6 NEOTROPICAL PSELAPHIDAE 



golden trichomes or specialized tufts of setae developed frequently on the 

 elytra and abdomen. These trichomes are characteristic of the symphiles, in 

 particular of the clavigerines, and the trichome secretion is highly stimulating 

 to the ant host, the workers of the latter licking and sucking these hair tufts 

 assiduously. (3) The inconspicuous, modified mouth-parts, clothed with golden 

 pubescence fitted for scraping, licking, and sucking. (4) The inordinately 

 modified antennae. (5) The deliberate, rather clock-like precision of their 

 unhurried walk within the hurry of the nest. (6) The habit of twirling the 

 antennae when approached by a host worker. The ecology of the European 

 Claviger has been discussed rather fully by Donisthorpe (1927), Hetschko 

 (1896), Krueger (1910), Mueller (1818) and Wasmann (I.e.), and our own 

 Adranes has been investigated (Park, 1932) sufficiently to state that these 

 clavigerids are cared for by the host, e.g. fed regurgitated liquid food, licked, 

 and even transported back and forth in the nest. 



These guest pselaphids have been the subject, then, of considerable re- 

 search; yet one may confidently state that only a minute part of this 

 fascinating field of comparative ecology has been explored. This is particularly 

 true of the many pselaphid synoeketes and the Clavigerinae. The careful study 

 of the many tropical species will richly repay the patience and ingenuity 

 necessary in this field. Even the tabulation of a complete check-list of Amer- 

 ican guest insects is lacking. The North American guests of ants, e.g. the 

 myrmecophiles (myrmecocoles in part) were listed by Hamilton (1888) and 

 much more completely by Schwarz (1890). Since then notable contributions 

 have been made by Wickham, one of the best students of our pselaphid fauna 

 (1892, 1896, 1898, 1900), and recently additional records have been given (Park, 

 1935a). 



The collection of this second group of pselaphids, the guest species, re- 

 quires a great deal of time, since close examination is essential. Once the 

 nest is located, it must be examined with care and piece-meal. Rough handling 

 and breaking of many galleries will allow most if not all of the contained 

 beetles to escape. The latter may be found anywhere in the nest. In general, 

 the synoeketes such as Batrisodes may be more frequent in the superficial 

 galleries, but the symphiles {Adranes, Fustiger) and other synoeketes 

 (Ceophyllus) tend to haunt the brood chambers and must be sought for in 

 the depths of the nest. When the nest is first opened, the beetles are seldom dis- 

 covered immediately unless their infestation is very high. Rather they tend to 

 crouch against the walls of the galleries, or crawl slowly into intact areas. This 

 is in marked contrast to the hurry and bustle of the host workers. After the 

 latter have adjusted to the emergency and begin the orderly carrying away 

 of their aphids, brood, and food, and begin their normal routine of recon- 

 struction, the pselaphids should be sought for as smaller, much slower-moving 

 forms; their precise, peculiar method of walking will serve to distinguish them. 

 Smoke blown into the mouth of a gallery often drives the inmates forth. If 

 after an hour at a good-sized nest no pselaphids are apprehended, another 



