CLASSIFICATION 51 



arrangement and are not intended to indicate anything as to the 

 relationship of the groups concerned. The tables are for three 

 different ages of each species, first, for those of the first nymphal 

 stage which would include males and females since the sexes are 

 indistinguishable in this stage ; second, for those of the other 

 nymphal stages of the female, one, two or more as the case may be ; 

 and third, for those of the adult female. There has been included 

 in this last table in certain of the subheads such nymphal struc- 

 tures as would make the table more usable, definite, and exclusive. 

 I am aware that the two tables for the separation of nymphs are 

 very inadequate and experience will undoubtedly show that they 

 are defective. They are offered even with their imperfections in 

 hopes that they may at times prove of value and also that the various 

 students of the Coccidae may be led to record observations that 

 will make possible the removal of the imperfections, so that better 

 tables for the separation of the nymphal stages can be constructed. 

 Experience has shown that in many if not all of the subfamilies, 

 there are characters present in the nymphal stages that are not 

 only more easily observed but more fixed than many of the char- 

 acters found in the adult females. 



Tables for the separation of the subfamilies as well as all the 

 later tables follow an exact dichotomous arrangement. While 

 tables of this sort require more space because of the indentation 

 of the paragraphs, this is more than compensated for by the ease 

 with which the rank of the paragraphs can be recognized through 

 the difference in the indentation. The difference in rank is further 

 shown by the numbering of the paragraphs with the letters of the 

 alphabet, the sequence of the letters showing the relative rank of 

 the paragraph. In using the tables the statement of characters 

 given under paragraph a and aa should be read and carefully 

 compared. The specimen should then be examined and compared 

 with the statement of characters given under a and aa and the 

 question decided as to which of these statements describe the 

 characters found in the individual examined. If the specimen 

 agrees with the characterization given under a, the other paragraphs 

 given under a should be examined and all those under aa should 

 be disregarded. Read the characterizations given under b and bb 

 and determine with which of these the specimen agrees. If the 

 specimen agrees with b, disregard the paragraphs under bb and then 

 determine in the same way whether it agrees with c or cc, d or dd, 

 e or ee, etc., or until the name of a subfamily has been reached. 



