266 Annals Entomological Society of America [Vol. X, 



of certain South African species of Coccidce. Reference to this 

 paper, however, led the writer to adopt the plan of the curves 

 as originally used, and not to adopt the method used by Brain. 

 To the writer, as well as others who have inspected this paper, 

 the curves shown herein are to be preferred over those of 

 Brain's, for they give the general trend of the individual curves, 

 the general trend of the curves of the species as a whole, and 

 the mean curve of the species. 



According to Cockerell (4) : "the curves will of course vary, 

 hardly any two antennas being exactly alike; but except for 

 abnormalities (pathological specimens), nearly every species 

 gives quite different curves, while two species, very different 

 in other respects, will give nearly the same curve. Some of the 

 widely distributed species give curves almost too variable to be 

 of much service, but in these cases, it is possible that the 

 material contains more than one thing." 



Brain (6) summarizes the taxonomic value of antennal 

 segments of Coccidce as follows: "The lengths of the antennal 

 segments are of great importance in the determination of 

 species if the measurements are accurately made from stained 

 specimens and properly tabulated." "The most useful arrange- 

 ment of antennal data seems to be arrived at by giving the 

 range of variation in the measurements of the different seg- 

 ments, with the addition, perhaps, of the mode of each. After 

 working over a large series of slides, one is impressed with the 

 characteristic appearance of the different antennae. But this 

 difference is difficult to express. The nearest approach is 

 obtained by a" graphic representation of the lengths of the 

 antennal segments, "and this supplies a most useful aid for the 

 preliminary location of an insect from slide specimens." "Sim- 

 ilarity of antennal curves, while indicating similarity of antennal 

 formulas, does not of necessity indicate identity of species, but 

 it does give a clue to work upon and possibly at times indicates 

 relationships." 



The writer is led to believe that these graphs are one of the 

 main characterizing taxonomic features, and this view has been 

 strengthened and sustained by several incidents and observa- 

 tions, among which the following will clearly illustrate their 

 importance. 



Several lots of Pseudococcids were collected b}^ the writer, 

 one of these in early spring of 1916 under the rough bark of 



