Maskell. — On New Zealand Coccidfe. 291 



Aet. XXXVII. — Further Notes on New Zealand Cocoidfe. 

 By W. M. Maskell. 



Plate VII. 

 [Read before the Philosophical Institute of Canterbury, 5th Jtme, 1879.] 

 I HAVE a few new species of Coccid^ to describe ; but I must first correct 

 some errors in my former paper.* 



I included last year amongst the Coccidge 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 Aphid^ ; 2nd, the Dimera, including Psyllidffi and 

 Aleyi'odidge ; and 3rd, the Monomera, or Coccidfe. In some of their stages, 

 the 2nd and 3rd 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 Aleyrodidse. 

 This family is perhaps more anomalous than the Coccidse, inasmuch as 

 Aleyrodes in its earlier stages is scarcely distinguishable from Lecaniuin, 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 Cuccid. 

 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 Aleyrodidse. I have no means at present of distinguishing 

 between my Powellia or Asterochiton and the European species of the family. 

 In the absence of evidence, I leave the names as they are, eliminating the 

 insects fi-om the Coccidse. 



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 

 A^ihis. 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- 

 sjjorum, 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. XI., Art, XYI. 



