MASKELL.— On New Zealand Coccide. 291 
Art. XXXVII.—Further Notes on New Zealand Coccide. 
W. M. MaskELr. 
Plate VII. 
[Read before the Philosophical Institute of Canterbury, 5th June, 1879.] 
I mave a few new species of Coccide to describe ; but I must first correct 
some errors in my former paper.* 
I included last year amongst the Coccidæ some insects, to which I gave 
the names of Asterochiton and Powellia. Further investigation has shown 
me that these have to be eliminated. The Order Homoptera is divided into 
three Classes, distinguished by the number of joints of the tarsus :—1st, the 
Trimera, including the Aphids ; 2nd, the Dimera, including Psyllide and 
Aleyrodide ; and 8rd, the Monomera, or Coccidæ. In some of their stages, 
the 2nd and 8rd Classes much resemble each other, and my error of last 
year was caused in a great measure from the fact that the specimens 
examined presented monomerous tarsi. I have, however, since been fortu- 
nate enough to procure a more complete series of these insects, and must 
now relegate both of them to the Dimerous Homoptera, family Aleyrodide. 
This family is perhaps more anomalous than the Coccide, inasmuch as 
Aleyrodes in its earlier stages is scarcely distinguishable from Lecanium, but 
in the adult form widely diverges. In my Asterochiton, for instance, only 
the closest inspection will detect the difference ; whilst in Powellia the 
double claw alone (except in the last stage) renders it certainly not a Coccid. 
However, there is now no doubt, for the adult insects which I have collected 
have 2-jointed tarsi, double claws, and four broad floury wings,—characters 
peculiar to Aleyrodide. I have no means at present of distinguishing 
between my Powellia or Asterochiton and the European species of the family. 
Tn the absence of evidence, I leave the names as they are, eliminating the 
insects from the Coccide. 
I may remark on the extreme closeness with which the families of the 
Homoptera run, as it were, one into another. The gradation from Lecanium 
to the earlier stages of Aleyrodes is imperceptible ; Aleyrodes has many 
features closely resembling Psylla; and Psylla is linked intimately with 
Aphis. On the young shoots of Eucalyptus there is, as I said last year, an 
insect much resembling in some features my Powellia, and this is, I believe, 
a Psylla. ; 
My specimens of Powellia vitreo-radiata were from Discaria and Pitto- 
sporum. I have found, on Olearia ilicifolia, another species, wanting the 
long glassy fringe of the earlier stage, and having, instead, a row of lanceo- 
late spines. I would call this species P. doryphora. 
* Trans. N.Z. Inst., Vol. XL, Art, XVI. 
