TAXONOMIC VALUE OF MORPHOLOGICAL CHARACTERS 27 



takes place. An examination of larvae of the males of several species 

 has revealed no characters by which the species can be determined. 



Adult Male 



The adult male is alate in some species and apterous in others, 

 although the wings are usually present. Except for this character most 

 of the males present few features that can be utilized for systematic pur- 

 poses, and the difficulty of procuring specimens effectually precludes their 

 use. Attempts to found genera or subgenera upon the character of the 

 males alone, as has in one or two instances been done, are hardly to be 

 commended. The primary purpose of this paper being to aid in the de- 

 termination of species, the males have been used only in cases where 

 such action could not well be avoided. 



SECRETIONS 



The nature and disposition of the waxy secretions have been much 

 relied upon in this group for specific differentiation and even to some 

 degree in the formation of generic concepts. The fact has consistently 

 been ignored by some authors, that these secretions are not the insect 

 itself, and little or no attempt has been made to correlate them with mor- 

 phological characters. Furthermore the fact has frequently been over- 

 looked that similarity in secretionary covering does not of necessity imply 

 similarity in structure. We thus have Erium lichtensioides redescribed 

 as Eriococcus artemisiae and Crypt or ipersia salina likewise referred to 

 Eriococcus solely on the basis of the fact that both are enclosed in a com- 

 plete sac, although neither has anything to do with the genus Eriococcus. 

 For the same reason we have the published record of the occurrence of 

 a certain species of Eriococcus in Japan, while the specimens upon which 

 the record was based are of a species of Antonina. We have Pseudo- 

 coccus eriogoni referred to the genus Erium because it is enclosed in a 

 sac, although it certainly has little else in common with the type of that 

 genus. Nor is this by any means the complete list of such errors. 



In this connection we may recall the words of Maskell (8) which 

 might well serve as the creed of Coccidologists, "On the other hand 

 (rightly as it seems to me), I have always insisted that true Coccid class- 

 ification should depend upon the anatomical characters of the insects 

 themselves, and that mere external features, visible to the naked eye or 

 an ordinary lens, are but secondary." It is only through the unreserved 

 acceptance of this idea with the adoption of the methods necessary in 

 order to carry it out that progress in the study of this group can be made. 



All of this is not to be interpreted as a contention that the secretions 

 are entirely valueless for taxonomic purposes. There unquestionably 

 exists a very close correlation between the nature of the secretions and 



