

THE COCCIDAE OF SOUTH AFRICA — H. 115 



glands ; (4) number and arrangement of marginal gland openings ; (5) number and 

 position of spines ; and (6) number and position of dorsal glands. 



To facilitate the comparison of species, particularly with reference to the above 

 characters, a formula is included in many of the descriptions. The type of formula 

 follows that used by Dr. L. Lindinger in his work on European Cocctdae (Die 

 Schildlause, 1912), but it has been altered and adapted to the requirements of this 

 work. All formulae read from the median line of the pygidium. 



L indicates lobes ; the position is indicated by figures placed below, as L ls L 2 , etc. 

 Thus L x indicates the median lobe, L„ the first lateral lobe or lobe in the 

 2nd position, etc. 



11 indicates a lobe composed of two lobules. 



P indicates plates with the position indicated as for lobes. 



— ■ indicates a vacant space in the margin of the pygidium. 



■G indicates gland openings on the margin. 



S indicates spine on the margin. 



N.B. — G and S are not used unless the parts indicated form a distinctive characteristic 

 of the pygidium, and glands or spines set within the margin are not 

 indicated. When more than one plate is present at any point the number 

 is indicated by a figure in front of the character : thus 2P X indicates two 

 plates before the median lobe. 

 For example, L x , P 2 , U 2 , P 3 , G, G, P 4 , G, G, P s , G, — , G, P 6 . (C. nataknsis) 



In using the above characters it will be found that every species does not have 

 •a distinctive formula. Thus Chrysomphalus aurantii, the common Red Scale has : — 

 J? v L x , 2P 2 , L 2 , 3P 3 , L s , 3P 4 , and this is also the formula for C. ficus and C. dictyo- 

 spermi. Nevertheless, the value of such a formula as a means of comparison is great, 

 and the tabulation of pygidial characters is facilitated and shortened. 



The number and arrangement of the circumgenital glands are also given in tabular 

 form. Thus in Diaspis bromeliae there are five groups of glands arranged in an 

 anterior median group and two lateral groups on each side. This would be stated : — 

 Circumgenital glands in 5 groups : — 



7—11 



13—21 13—21 



12—18 12—18 



indicating that the median group consists of from 7 to 11 glands, the anterior laterals 



of 13 to 21 each, and the posterior laterals of 12 to 18 each. 



Synoptical Key to South African Genera of the Diaspinae. 



A. cj puparium somewhat similar to the $ scale in general form and texture, being 



usually smaller and more elongate. 



B. Exuviae of $ scale + central and superposed ; $ scale circular or nearly so. 



C. Adult $ not enclosed in the second pellicle. 



(1) $ scale with thin margins, not recurved to make it capsular ; pygidium without 

 elongated thickenings (paraphyses) ; plates absent, simple or branched ; 

 circumgenital glands absent, or, when present, usually in 4 groups. 



Aspidiotus series. 



