1912] Pseudococcus of South Africa 187 
STAINING COCCIDAE FOR DETERMINATION, WITH SPECIAL 
REFERENCE TO THE GENUS PSEUDOCOCCUS. 
During 1910, and the first part of 1911 the writer collected 
material in the vicinity of Capetown, South Africa, for the 
purpose of determining what species of the Genus Pseudococcus 
Westwood, were to be found in that locality. Specimens were 
obtained from twenty-one different kinds of plants, and a 
series of experiments made to determine which was the most 
satisfactory way of mounting them for study. Everyone who 
has worked with this genus will appreciate the difficulties 
encountered in the determination of species, and also the 
unsatisfactory nature of the majority of the descriptions given 
for described species. Most of these descriptions simply give 
the size, color, amount of waxy covering, antennal formula and 
host plant. If different descriptions of the same species are 
available it will at once be seen how variable are the facts 
given. Smith* (1911) discusses this fact and shows the futility 
of many of the specific characters generally used. 
Notwithstanding the fact that the mere antennal formula is 
of little value, the relative size of the antenne as a whole, and 
of the segments separately, is a very useful character when the 
actual measurements are given. This, together with the average 
size of the adult @ at the time of oviposition, the comparative 
lengths of the sete of the anal lobes with those of the anal 
ring, the nature of the integument and the distribution of 
pores and spines, furnish, I believe, the best characters 
obtainable. 
For all these characters, except the length of the individuals, 
specimens cleared and mounted in the usual manner are not 
the most satisfactory. With regard to the joints of the 
antenne especially does this apply, for such specimens are too 
clear, and the distinction between the joint itself and the 
conjunctiva is indistinct. Referring to this fact, Smith (loc. cit. 
p. 313) states: ‘‘The chitin is not continuous from one segment 
to the next and consequently the portion between the chitinous 
parts of the segments, the conjunctiva, is not visible or only 
slightly so in well cleared specimens. Consequently, in making 
P. E. Smith. ‘‘ Specific Characters of the Genus Pseudococcus.’’ Ann. Ent. 
Soc. Am. IV, No. 3. Sept., 1911. 
