134 
Transactions of the Boyal Society of South Africa. 
I was inclined at first to consider it as a distinct species, because no 
single description is adequate, but, considering the range of variation 
shown in other localities, and the possibility of an insect being spread with 
greenhouse plants, etc., I have decided rather to retain the South African 
form under Ps. virgatiis Ckll., and give the measurements of legs, antennae, 
etc., in full, in the hope that some one who has access to a greater range 
of material — such as is at present in the Washington Collection — will 
compare the insects from different localities in detail. 
In the original description of Ps. virgatus (Ckll.) the size of the adult 
5 is given as 4*5 mm. ; var. b is 3*5 mm. long; var. d "2 mm. — not 
adult"; Ps. virgatus madagascariensis Newstead is said to be ''consider- 
ably longer and broader than typical examples of Ps. virgatus (Ckll.)." 
The South African forms are 3 to 3*5 mm. in length, i.e. identical in size 
with D. ceriferus Newst. The size is not given for D. talini Green 
(loc. cit.). 
The references to the mealy secretion vary, but this is readily under- 
stood as the young females are lighter in colour and do not exhibit the 
submedian dark patches and the character of the delicate filaments and 
also of the caudal, waxy projections vary according to whether the insect 
is in a sheltered position or not. They are also easily dislodged in 
packing. It would be quite impossible to determine the character of 
these appendages from spirit material. 
The dermal characteristics are not always described, so comparison 
is impossible, but the " circular spinnerets " mentioned by Prof. Newstead 
in his Ps. ceriferus and Ps. virgatus madagascariensis are present in the 
South African specimens. 
The antennal measurements are given in jx as follows : — 
Tinsley in the Canadian Entomologist, vol. xxx., 1898, p. 222, gives 
measurements of type material from Jamaica : — (1) 45-60 ; (2) 55-80 ; 
(3) 85-95 ; (4) 45-55 ; (5) 50-65 ; (6) 55-60 ; (7) 53 ; (8) 115-120. Ceylon 
material :— (1) 59-65 ; (2) 67-76 ; (3) 90-104 ; (4) 53-57 ; (5) 53-65 ; 
(6) 51-62; (7) 56-62; (8) 120-127. Mexican material :— Mr. Tinsley 
writes : " I have also recently examined specimens from Mexico, and find 
them to fall between the Jamaica and Ceylon specimens in size. It will 
be noticed that the Ceylon specimens are longer than those from Jamaica." 
In the description of Ps. virgatus var. (Davenport, Academy of Science, 
X., p. 130, 1905) Cockerell gives the following antennal measurements : — 
(1) 50; (2) 63-65; (3) 70-72; (4) 37-42; (5) 40-45; (6) 43-47; (7) 
45-47 ; (8) 100. 
The South African specimens vary between the limits : — (1) 51-61 ; 
(2) 64-74; (3) 71-85; (4) 37-51; (5) 44-58; (6) 44-54; (7) 48-54; 
(8) 108-120. 
It will be observed that this material most nearly approaches the 
