TAXONOMIC VALUE OF ANTENNAL SEGMENTS OF 

 CERTAIN COCCIDAE- 



A. H. HoLLiXGER, Missouri Agricultural Experiment Station. 



During the past two seasons the writer has been making 

 special investigation of the CoccidcB of Missouri, and during 

 that time many interesting forms, Diaspincc as well as others, 

 have been found, including several new and rare species. The 

 Diaspince, while presenting certain problems in themselves, are 

 not nearly so perplexing as are the mealy bugs, including 

 Phenacoccus, Pseudococciis, and Trionymus, the Eriococcids, the 

 Lecania, and other genera of the CoccincE. While it is a compar- 

 atively simple matter to identify armored scale insects by 

 means of the pygidia, it has been an almost impossible task for 

 the average entomologist to separate the different species of 

 the so-called soft scales, due to the fact that there have been 

 very few constant, tangible characters for comparison in this 

 broad group. Some writers have made a study of the fringe of 

 setae and accompanying gland pores surrounding the anal 

 openings in certain of the mealy bugs (5) . Others have studied 

 the cerarii (5) which are the grouped conical spines and accom- 

 panying gland pores along the sides of certain of the mealy 

 bugs. A few have elaborated on the structures of the anal 

 plates of the Lecania (2). Many others have attempted to 

 characterize species of Coccidce by establishing a formula for 

 the lengths of the antennal segments. While each of these 

 may be of some value in strict systematic work, the practica- 

 bility of using any one of these for easy identification of species 

 is slight, at best. What is needed in coccidology is to put the 

 study of soft scales upon a practical working basis, and so it 

 was with this aim in view that the writer has given much of his 

 time to close inspection and careful comparative study of the 

 several genera of the native soft scale insects. 



Cockerell's note (4), in which mention was made concerning 

 the value of antennal segments in the determination of coccid 

 species when antennal curves were plotted, led the writer to 

 investigate this method. 



There has been much debate among entomologists as to 

 whether or not antennae in coccids are of any taxonomic value. 



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