Exchanges 



EXCHANGES 



One of the best ways of adding to a collection is by the method 

 known as exchanging. A collector in one part of the country 

 may find species which are rare, or altogether unknown, in an- 

 other part of the country. By a system of exchanges with 

 other collectors he is able to supply the gaps which may exist in 

 his collection. No one, however, cares to effect exchanges with 

 collectors who are careless or slovenly in the preparation of their 

 specimens, or inaccurate in naming them. A collector who con- 

 templates making an exchange should, as the first step, prepare 

 double lists, in one of which he gives the names and the number 

 of specimens of either sex of the butterflies which he is able to offer 

 in exchange; -in the other he sets forth the things which he 

 desires to obtain. The first list is said to be a list of " offerta " ; 

 the second is a list of "desiderata." As an illustration of the 

 manner in which such lists may be conveniently arranged, I give 

 the following: 



OFFERTA 



Papilio turnus, tf 3; 9 4- 



Dimorphic var. glaucus, 9 6. 

 Colias alexandra, c? 4> 9 6. 



DESIDERATA 



Papilio nitra, 9 



Papilio brevicauda, orange-spotted var. 



The collector who receives these lists of offerta and desiderata 

 will be able to decide what his correspondent has which he de- 

 sires, and what there may be in his own collection which the 

 correspondent wishes that he can offer in exchange; and the 

 process of exchange is thus immediately facilitated. 



Persons who exchange insects with others should always be 

 extremely careful as to the manner of packing the specimens, 

 and the directions given in the introductory portion of this book 

 should be very carefully followed. Too much care cannot be taken 

 in preventing damage to specimens in transit. 



Genus ANCYLOXYPHA, Felder 



Butterfly. Very small, the antennae very short, the club 

 straight, bluntly pointed. The palpi have the third joint long, 



344 



