68 Aonictia. 



AONIDIA, Targ. Tozz. 



In this genus the development commences as in Aspidtohes, but is arrested 

 at the stage already noticed in the description of Asp. secreitis. The adult 

 female, at the time of the second moult, decreases in size and is entirely 

 enveloped by the second pellicle. Within this receptacle it passes the re- 

 mainder of its existence and deposits its eggs, or rather young, for all the 

 species at present known are apparently ovoviviparous. The female puparium 

 is principally composed of the second pellicle, which is proportionately large, 

 and its form is dependent upon that of the pellicle, varying from sub-circular to 

 oblong oval, or, as in A. bullata, with a distinct posterior extension. The first 

 pellicle is approximately central, and may bear secretionary appendages ; in 

 A. comiger glassy horns are developed, while A. btdlata produces a ball of 

 cottony secretion in its larval stage. The ventral scale is complete, consisting 

 of the ventral part of the second pellicle. The overlying secretion covering the 

 dorsal scale is of a very firm structure, resisting the action of liquor potassas. 

 After maceration it frequently comes away in one complete piece together with 

 the first pellicle, forming the ' superimposed scale ' noticed by Signoret. 



The male puparium usually resembles superficially that of the female, and is 

 of almost the same size. It consists of secretionary matter, with the single 

 pellicle placed near the centre. 



The adult female, which at first nearly fills the cavity of the second pellicle, 

 gradually shrinks until it is less than half the size of the second stage, this 

 shrinkage taking place principally from the posterior extremity. Towards the 

 end of its existence the adult female occupies little more than the cephalic 

 area of the second pellicle. The thoracic segments are much broader than the 

 abdominal. The antennas are rudimentary ; the mouth-parts are usually rather 

 large. The pygidium is very variable in the form of its margin, some species 

 being without true lobes, others having as many as eight. There are no 

 circumgenital glands, and often no tubular spinnerets. The absence of the 

 glands indicates an ovoviviparous habit ; the tubular spinnerets have presumably 

 disappeared through disuse, the scale being secreted during the second stage 

 of the insect. The genital aperture is usually close to the base of the pygidium 

 on the ventral surface. The anal aperture is much nearer the extremity on the 

 dorsal surface, and the lining of the rectum is usually thickened and strongly 

 chitinised. 



The adult male, in the single species observed, resembles that of Aspidiotus. 



Synopsis of Species. 



A. Larval pellicle with secretionary appendages, 



{a) Scale sub circular; first pellicle bearing glassy horns ... comiger. 

 {b) Scale with distinct posterior extension ; larval pellicle 



with a cottony tuft bullata. 



B. Larval pellicle without secretionary appendages. 



{a) Scale cordate ; forming shallow pits in stem of plant ... lorajifhi. 

 (b) Scale oval ; not forming pits obsctira. 



