66 Transactions. — Zoology. 



numerable mistakes and confusion. The proper way to study 

 this family is to give to every species very close and minute 

 investigation, and rather to wait weeks or months before 

 naming a species than to define it on the hasty examination 

 of a few minutes. Now, not only will Coccids as between 

 themselves easily mislead a believer in " similarity of habit," 

 but they will induce him to include amongst them forms 

 which are not Coccid at all. For example, Lecanium haccatum 

 has almost every external character of a Kermes : Prosopo- 

 phora dendrohii is outwardly very much like a Lecanid ; or, 

 to take a still clearer case, it is just the judging by external 

 characters which has led some observers to place Planclionia 

 in the Lecaniodiaspinse, and make terrible confusion. These 

 are all Coccids ; but " similarity of habit " would make us 

 mix all sorts of families together. Cynipids make woody 

 galls, so do some Chalcids, so do some Psyllids. And the 

 force of this is clearly shown in Mr. Tepper's own paper, 

 where he includes as a Coccid a form which he names 

 " Ascelis (?) multitiidinea," and which is most certainly the 

 gall made by a Psyllid of the genus Trioza. Neither the 

 naked eye nor a lens can distinguish this gall from that of a 

 Coccid, yet it is certainly not so. 



Everybody is liable to make absurd -mistakes. In 1878, 

 just because I did not take sufficient trouble, I included a 

 Psyllid and two Aleurodids amongst Coccids : and Signoret 

 himself wanted to make a new Coccid genus, Spondyliaspis , 

 out of an Australian Psyllid making a waxy scale. There is 

 not the slightest fault, therefore, to be found with Mr. Tepper 

 for his error about Ascclis. But when it comes to proposing 

 a classification founded upon " general similarity of habit," a 

 protest is necessary, and I am compelled to adhere to my 

 system, under which neither Cylindrococcus nor SphcRrococcus 

 can enter the sub-family Brachyscelinae. 



Finally, I have myself to eat humble pie; and, bowing to 

 the voice of the majority, to withdraw my nomenclature of the 

 past as regards the names of grouj^s and sub-families. In 

 this paper, therefore, I write Lecanince, Dactylopince, &c., and 

 trust that whatever good there may be in my work may not 

 be obscured or neutralised by any orthographical crimes. 



Group DIASPIDIN^. 



Genus Aspidiotus. 

 Aspidiotus casuarinee, sp. nov. Plate III., figs. 1-3. 



Female puparium dark yellowish-brown ; circular, rather 

 convex ; pellicles yellow. Diameter about -^^in. 



Male puparium brown, the posterior end whitish ; form 

 elongated, subcylindrical, slightly convex, not carinated. 



