METHODS OF COLLECTING 7 



nest should be opened, or the original one placed in a bag and reserved for 

 more detailed study. 



One point should be emphasized. When the guest pselaphids are collected, 

 they should be accompanied by a goodly series of the host, and the guests and 

 host should be kept together with a note number so that later the observ^ations 

 recorded in the field can be allocated to the proper specimens. The host should 

 be mounted on the same pin as the beetle. Without this precaution the col- 

 lection cannot be said to be really complete. 



Ant nests on hillsides, meadows, marginal nests in forest clearings, be- 

 neath road-side debris, about the borders of ponds and in rich forests will yield 

 interesting pselaphid guests. Nests beneath stones seem to be especially good, 

 as are also the large nests of Lasius aphidicola, flavus, and related forms. The 

 workers of the latter ants are honey yellow in color, numerous, tend aphids 

 and coccids and usually nest in rotting logs and the soil beneath decaying logs 

 and stumps. Their nests often have a characteristic, pleasingly aromatic odor. 

 In these nests Ceophyllus and Adranes are most frequently found. 



The log-nesting Aphaenogaster tennesseensis harbors many species of 

 pselaphids {Batnsodes, Tmesiphorus, Cercocerus, Cedius) but the beetles are 

 not easy to obtain, since the host often tunnels in firm wood. The related 

 Aphaenogaster julva, often nesting in more rotten logs, although the occasional 

 host of Tmesiphorus, is not generally productive of pselaphids. 



The clearing ants, building around and in upland forest clearings, e.g. 

 Formica exsectoides and Formica ulkei, hold many guests in their large 

 cone mounds, among which some species of Batrisodes are to be found. 



A great variety of guest pselaphids are found, at infrequent intervals, in 

 the nests of the ubiquitous Losing niger americanus, e.g. Batrisodes, Ceophyllus, 

 Adranes. Details of host-guest relations, where available, are set down with 

 the taxonomic descriptions which follow, and the reader is also referred to the 

 list of hosts and their guests in the cases of certain genera. 



Although pselaphids may be collected in cyanide bottles or other standard 

 killing jars, such jars usually allow these tiny insects to become dirty, or even 

 lost, and it is difficult to keep ant host and guest together. I have found num- 

 bered vials of 95 per cent ethyl alcohol to be the best collecting medium. The 

 pselaphids should not be picked up with forceps; a suction bottle is good, but 

 a small camel-hair paint brush is superior. Once the pselaphid is discovered, 

 it is the work of a few seconds to moisten the tip of the brush in the alcohol 

 and dab up the specimen. In this way specimens are kept segregated ecologic- 

 ally, clean and unbroken. 



Pselaphid collecting equipment then is simple, e.g. a small brush, alcohol 

 vials with note number, several stout sacks for carrying home mold samples 

 or ant nest, a small sharp hatchet and a notebook. A good hand lens of ten 

 diameters' magnification, or better, a watch-maker's eye-glass or a Berger 

 Loop head-glass are helpful for the examination of small pieces of the habitat. 

 This latter is often facilitated by a small electric torch, especially in deep 

 forests or for collecting at dusk. 



