April, "OS] JOURNAL OF ECONOMIC ENTOMOLOGY 93 



termining this the key is ahnost indispensable. The upper left-hand 

 corner is always reserved for the decimal number associated with the 

 proper subject. The scientific name of the species considered appears 

 at the top and middle of the card. Below the species name is given 

 the subject heading, locality, date, etc. The author's name should 

 also appear on each note. 



The decimal numbering may be conveniently done by a specially 

 constructed rubber stamp made after the manner of the ordinary 

 band dating stamps. This special stamp should have at least six 

 bands, each bearing in vertical line the following fifteen characters as 

 separated by dashes: 1— 2— 3— 4— 5— 6— 7— 8— 9—0— .—,— :— (—) 

 Space cannot be taken here for a discussion of the proper use of the 

 comma, colon and parentheses. It is the same as in the Dewey 

 System. 



The use of guide cards. In the key itself, guide cards are used 

 for indicating only the primary divisions: Generalia, Work, Life 

 History, etc. It is well to list on the guide card the next series of 

 subdivisional headings occurring under it. 



Among the notes to be filed, guide cards should, of course, be used 

 for each species and headed with the names of the order, genus and 

 species. Beyond this the use of guides is purely a matter of personal 

 convenience and the filer may decide for himself whether he cares to 

 give any special significance to the color of card, size of tabs, etc. The 

 guides in no way alter or interfere with the application of the key. 



Cross-references. If the subject matter on a card relates to more 

 than one insect, a cross reference card is made and filed under the 

 name of the other species, in the proper decimal sequence of the sub- 

 ject. Similarly, a cross reference is made if the record relates to 

 more than one topic in the study of one species or if the data may have 

 application to more than one topic. 



Amplification of key. Throughout the key there is ample room 

 for further development as may be required to adapt it more fully to 

 the study of any new subject and insertions may be made as they 

 are found to be needed. It will be noted that in the series of main 

 divisional numbers, 8 and 9 are unoccupied. In these cases, as in 

 similar ones throughout the key, wherever numbers have been omitted 

 or are unoccupied, there is room for additional subjects of properly co- 

 ordinated character. Changes may be made to suit the user, either in 

 the wording or character of a subject heading to fit any special need, 

 but if there be room for addition of the needed subjects, it would 

 seem better to add than to substitute. In this way the key is ren- 

 dered more complete and generally applicable. Inappropriate head- 



